Final Report: Technical Feasibility of Subsurface Intake Designs for

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Final Report: Technical Feasibility of Subsurface

Intake Designs for the Proposed Poseidon Water Desalination

Facility at Huntington Beach, California

Authored by the Independent Scientific Technical Advisory Panel

Under the Auspices of the California Coastal

Commission and Poseidon Resources (Surfside) LLC

Convened and Facilitated by CONCUR, Inc.

October 9, 2014

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Table of Contents

i. List of Tables and Figures .............................................................................................................................. 4 ii. Conveners’ Supplemental Preface ................................................................................................................ 5 iii. Signature Page ............................................................................................................................................ 10 iv. Panelists’ Executive Summary ................................................................................................................... 11

Chapter I. INTRODUCTION ....................................................................................................... 19 1.1 General ................................................................................................................................................... 21 1.2 Environmental ....................................................................................................................................... 21 1.3 Economical ............................................................................................................................................. 21 1.4 Hydrological .......................................................................................................................................... 22 1.5 Seismic activity ...................................................................................................................................... 22 1.6 Oceanographic setting ......................................................................................................................... 22 1.7 Constructability .................................................................................................................................... 23

Chapter II. APPROACH ................................................................................................................ 25 2.1 Introduction .............................................................................................................................................. 25 2.2 Potential technologies that meet hydraulic capacity goals .............................................................. 27

Chapter III. Subsurface Intake Options Considered ............................................................... 29 3.1 Introduction .............................................................................................................................................. 29 3.2 Hydrogeology of the Huntington Beach area ..................................................................................... 30 3.3 Well intake systems .................................................................................................................................. 32

3.3.1 Introduction ............................................................................................................................................................ 32 3.3.2 Vertical wells completed above upper confining unit ............................................................................. 32 3.3.3 Vertical wells completed below confining unit ......................................................................................... 33 3.3.4 Vertical wells completed above and below confining unit .................................................................... 34 3.3.5 Radial collector in shallow aquifer ................................................................................................................. 35 3.3.6 Slant wells completed in shallow aquifer ..................................................................................................... 36 3.3.7 Horizontal directionally drilled (HDD) wells underneath the sea floor ............................................. 38

3.4 Gallery intake systems ............................................................................................................................ 39 3.4.1 Introduction ............................................................................................................................................................ 39 3.4.2 Surf zone infiltration galleries ......................................................................................................................... 39 3.4.3 Engineered seafloor infiltration galleries (SIGs) ....................................................................................... 41

3.5 Water tunnels ............................................................................................................................................ 43 3.6 Discussion ................................................................................................................................................... 44

Chapter IV. DISCUSSION OF FEASIBILITY CRITERIA .................................................. 46 4.1 Introduction ........................................................................................................................................... 46 4.2 Hydrogeological Feasibility Factor ................................................................................................... 47

4.2.1 Impacts on freshwater aquifers .................................................................................................................... 47 4.2.2 Potential yields per installation ................................................................................................................... 47

4.3 Design Constraints ............................................................................................................................... 47 4.3.1 Units required for 127 MGD ........................................................................................................................ 47 4.3.2 Linear beachfront required ............................................................................................................................ 48

FINAL PHASE 1 REPORT

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4.3.3 Onshore footprint ............................................................................................................................................. 48 4.3.4 Scalability ........................................................................................................................................................... 48 4.3.5 Complexity of construction .......................................................................................................................... 49 4.3.6 Performance risk .............................................................................................................................................. 49 4.3.7 Reliability of intake system .......................................................................................................................... 49 4.3.8 Frequency of maintenance ............................................................................................................................ 50 4.3.9 Complexity of maintenance .......................................................................................................................... 50 4.3.10 Material constraints ....................................................................................................................................... 50

4.4 Oceanographic constraints ................................................................................................................. 51 4.4.1 Sensitivity of sea level rise ........................................................................................................................... 51 4.4.2 Sensitivity to Huntington Beach sedimentation rate ............................................................................ 51 4.4.3 Sensitivity to Huntington Beach bathymetry .......................................................................................... 51 4.4.4 Suitability of bottom environment conditions ........................................................................................ 52

4.5 Geochemical constraints ..................................................................................................................... 52 4.5.1 Risk of adverse fluid mixing ........................................................................................................................ 52 4.5.2 Risk of clogging ............................................................................................................................................... 52 4.5.3 Risk of changes on inorganic water chemistry ....................................................................................... 53

4.6 Precedents .............................................................................................................................................. 53

Chapter V. Evaluation of Subsurface Intake Types ................................................................. 54 5.1 Evaluation matrix ................................................................................................................................. 54 5.2 Subsurface intake type feasibility at Huntington Beach .............................................................. 54

5.2.1 Vertical wells completed above upper confining unit ......................................................................... 54 5.2.2 Vertical wells completed below confining unit ..................................................................................... 55 5.2.3 Vertical wells completed above and below confining unit ................................................................ 55 5.2.4 Radial collector in shallow aquifer ............................................................................................................ 55 5.2.5 Slant wells completed in Talbert aquifer .................................................................................................. 56 5.2.6 Engineered seafloor infiltration galleries (SIGs) ................................................................................... 56 5.2.7 Surf zone infiltration galleries ..................................................................................................................... 57 5.2.8 Horizontal directionally drilled (HDD) wells underneath the sea floor ......................................... 58 5.2.9 Water tunnel ....................................................................................................................................................... 58

Chapter VI. Summary, Conclusions, and Recommendations for Phase 2 ........................... 63

Chapter VII. Bibliography – Reports on Subsurface Intakes ................................................ 67 7.1 Peer-reviewed publications, selected peer-reviewed conference papers, and books ................. 67 7.2 Conference papers, reports and support documents ....................................................................... 72 7.3 Posted literature ....................................................................................................................................... 73

Chapter VIII. APPENDICES ........................................................................................................ 75 8.1 APPENDIX A: Biographies of Panelists ............................................................................................. 75 8.2 APPENDIX B – Terms of Reference ................................................................................................... 80


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i. List of Tables and Figures

Page

Table ES-1 Subsurface Intake Summary Matrix 16

Figure 3.1. Hydrogeologic section from the Pacific Ocean through the Talbert Gap into the basin (from the Orange County Water Groundwater Master Plan and Edwards et al., 2009)

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Figure 3.2. Conceptual diagram of the beach well (from Missimer et al., 2013) 33

Figure 3.3. Conceptual diagram of the collector well (from Missimer et al., 2013) 35

Figure 3.4. Conceptual diagram of the slant well (from Missimer et al., 2013) 37

Figure 3.5. Conceptual diagram of the HDD wells at Huntington Beach (from Neodren, 2014) 38

Figure 3.6. Conceptual diagram of the beach gallery (from Maliva and Missimer, 2010) 41

Figure 3.7. Fukuoka, Japan SIG conceptual diagram (from Pankratz, 2006) 42

Figure 3.8. Conceptual design of a SIG for the Shuqaiq SWRO plant, Red Sea, Saudi Arabia (from Mantilla and Missimer, 2014)

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Figure 3.9. Conceptual diagram of a tunnel intake system proposed for another southern California SWRO plant

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Table 5-1 Subsurface Intake Summary Matrix 60 - 61


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ii. Conveners’ Supplemental Preface

This report evaluates whether any of several subsurface intake designs would be technically

feasible to build and operate as part of the Poseidon Resources (Surfside) LLC (Poseidon) seawater

desalination facility proposed for the City of Huntington Beach, California. This report is the product of

coastal development permit (CDP) review, the California Coastal Commission (CCC or the Commission)

recommendations, and a scientific and technical review conducted by an independent expert panel (the

Independent Scientific Technical Advisory Panel, or ISTAP) convened jointly by staff of the Commission

and Poseidon.

Background

In 2002, Poseidon submitted a CDP application to the City of Huntington Beach for a proposed

seawater desalination facility. In 2003, the City declined to certify the associated Final Environmental

Impact Report (EIR) for the proposed project. In 2005, Poseidon re-applied to the City with a modified

proposal. Later that year, the City certified the project EIR and in early 2006, approved a CDP for the

portions of the project within the City’s permit jurisdiction. That CDP was then appealed to the

Commission. In May 2006, Poseidon submitted a CDP application to the Commission for portions of the

proposed project in coastal waters offshore of Huntington Beach, which are within the Commission’s

retained permit jurisdiction.1

1 The California Coastal Act, established by voter initiative in 1972 and made permanent by the Legislature in 1976, includes specific policies meant to provide public access to the coast, protect coastal resources, and ensure appropriate development within the state’s Coastal Zone. The Coastal Zone extends along the length of the state and includes coastal waters to three miles offshore as well as areas ranging from several hundred feet to several miles inland from the shoreline.

Many forms of development proposed within the Coastal Zone are subject to provisions of the California Coastal Act and of Local Coastal Programs (LCPs), which are developed by local governments in association with the Coastal Commission. LCPs generally include more specific policies than those in the Act that reflect and more closely address locally important coastal resource issues.

Once the Coastal Commission certifies an LCP and an associated Land Use Plan (LUP), the local jurisdiction takes on most of the permitting authority provided by the Act. The Commission retains its permitting authority over state tidelands (i.e., offshore areas) and in areas of the Coastal Zone that aren’t covered by a certified LCP or LUP. There are also areas or types of projects within local jurisdictions where the local government has permitting authority, but where those permits can be appealed to the Commission. Proposed projects that would be located within both the permit jurisdiction of a local government and the Commission may require a CDP from each. This is the case for the proposed Poseidon Water desalination facility in Huntington Beach. Additionally, the proposed project is within the Commission’s appeal jurisdiction.


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By the end of 2010 the Commission had approved and issued a number of CDPs for desalination

facilities that used surface, subsurface, or screened intakes, including one issued to Poseidon for its

Carlsbad Desalination Project, the first large-scale project approved in the State of California. In addition,

the State Water Resources Control Board (State Board) had approved the Once Through Cooling Policy.

These events provided information that was useful for permit review for the Huntington Beach Project.

While the Commission was reviewing the CDP application and the appeal, Poseidon modified some

components of its proposed facility and submitted a proposed project re-configuration for the long-term

stand-alone operation of the desalination facility to the City, which required the City to conduct additional

California Environmental Quality Act (CEQA) review and consider a new CDP for the project. In 2010,

the City certified a Supplemental EIR and approved a new CDP, which was also appealed to the

Commission.

California Coastal Commission Action

In November 2013, the Commission held a public hearing to determine whether to issue a CDP to

Poseidon for the offshore portions of its proposed project and to determine how to resolve the appeal of

the City’s CDP. At that hearing, Commission staff recommended that the Commission conditionally

approve both CDPs with a requirement that Poseidon construct a subsurface intake unless Poseidon

presented additional information showing that intake method to be infeasible.

The hearing included several hours of public testimony and Commission deliberation, with one of

the key issues being whether (a) subsurface intake(s) is feasible at or near the proposed site. Near the end

of the hearing, several Commissioners recommended to Poseidon that it work with Commission staff to

develop independent verification of whether any of several subsurface intake designs would be feasible

for this project. Poseidon then withdrew its CDP application and the Commission voted to continue the

appeal of the local CDP.

Shortly after that hearing, and in anticipation of Poseidon’s submission of a new CDP application,

Commission staff and Poseidon began discussing how to produce an independent scientific and technical

review as recommended by the Commissioners. In January 2014, the two parties (known here as the


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“Conveners”) agreed to undertake an independent review, to be conducted in at least two phases. As part

of this process, Poseidon agreed to contract with CONCUR, Inc., a firm specializing in analysis and

resolution of complex environmental issues and in structuring independent review processes. While the

Commission is not contracting with CONCUR, the agency staff agreed on the choice of CONCUR as the

facilitator and convener of this independent review. CONCUR convened a panel of scientific experts –

the Independent Scientific and Technical Advisory Panel (ISTAP) – to review the issues at hand and

make recommendations to bolster the scientific underpinning of the permit application and review

process. For this first phase, the two parties and CONCUR identified the expertise needed on the Panel

and jointly agreed on the Panel members selected. The Panel’s specific and limited purpose during this

Phase I of the independent review was to investigate whether currently available alternative subsurface

intake technology can provide a technically feasible method of supplying source water to Poseidon’s

proposed desalination facility. Working with CONCUR, Commission staff and Poseidon agreed on the

Panel’s initial scope of work and on its structure and operating procedures. These are described in

Appendix B of this report, the Terms of Reference (TOR).

As noted above, the Conveners anticipate that multiple phases of work will be necessary for the

Panel to complete it’s charge, and that the composition of the Panel may be revised at each phase to

provide the necessary expertise. The Panel’s first phase of work was limited to evaluating the only the

technical feasibility of subsurface intake methods rather than the all aspects of feasibility. In other words,

the Panel was charged with investigating whether, given hydrogeologic and oceanographic site

conditions, any of several currently available subsurface intake methods can be built and operated at the

proposed Huntington Beach site. After agreeing upon the Panel composition, the Conveners also jointly

developed a bibliography and jointly provided data sources for the Panel to use in its deliberations.

Panel Deliberation Process

The Panel started its work in June 2014. The Panel’s initial organizational meeting, convened via

conference call, was focused on introducing the Panel members, the parties, and CONCUR, describing

and answering questions about the Terms of Reference, and establishing the expected schedule, review


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process, and other considerations. The parties posted relevant data, reports, and information for the Panel

on the Commission’s FTP site, with most being available to the interested public.

The Panel’s first public meeting was held on June 2014 in Huntington Beach. It included

presentations by Poseidon and technical advisors2, discussions among the Panel members, and

opportunities for public comment.

At this public meeting, the Panelists identified and requested additional information to support the

analysis of technical feasibility3. Several weeks later, at a work session in San Francisco, the Panel

evaluated the information made available through the FTP site, at the public meeting, and the additional

information they had requested, along with published literature known to the Panelists, and worked to

assess the technical feasibility of various subsurface intake designs.

2 Information provided to the Panel at that public meeting included:

• Slant Well Intake Investigation - Doheny Ocean Desalination Project - slant well technology at the proposed Doheny Beach desalination facility (presented by Richard Bell, a staff member from the Municipal Water District of Orange County.

• Groundwater Basin and Talbert Gap Overview - detailed information on the Talbert aquifer, local seawater barriers, local sediments, and the use of injection wells serving as water recharge points as well as seawater intrusion buffers (presented by Roy Herndon, a staff member of the Orange County Water District.

• Huntington Beach Project Site Characteristics - characteristics of the proposed Huntington Beach site, including site acreage, surrounding land use and existing infrastructure, and vegetation.

• Review of the Proposed Huntington Beach Project - the scope, goals, and status of the various phases of the Huntington Beach Project, the determination of “feasibility,” characteristics of the site, proximity to water delivery systems, and other project components.

• Oceanographic Considerations of Alternative Intakes for the Huntington Beach Desalination Facility - tidal currents in relation to sea floor shelves, interaction with mobile sediments, and other oceanographic considerations.

• Oceanographic Siting - detailed evaluation of the seabed infiltration gallery (SIG) oceanographic siting. • Conceptual design of a SIG. • Constructability assumptions and options for the conceptual SIG. • Alternate Intakes - the process undertaken in other desalination projects (particularly in California) to examine alternate

intakes systems. • Alternate Intake Technologies - evaluation at the Huntington Beach site.

3The parties jointly provided the identified information including:

• CCC Nov 2013 Report and Background documents used to evaluate alternatives, • San Diego County Water Authority (SDCWA) – Feasibility Study for Intake Options, • Commission’s Draft Sea Level Rise Policy Guidance document, • Sediment management (disposal/reuse) policy excerpts from the Commission, • Poseidon’s proposed Vibracore sampling methodology, • Studies comparing intake alternatives and key factors in determining feasibility, • Poseidon’s site specific Vibracore data re: determination of range of hydraulic conductivity/K-values, • Poseidon’s documents used to determine the configuration of proposed intake structures, and • Documents used to assess hydraulic challenges of the current SIG design/technology.


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The Panel’s work continued in subsequent weeks through conference calls, drafting of writing

assignments, and exchange of several iterations of its draft reports. To maintain the Panel’s independence,

the report preparations and Panel deliberations occurred without input from the Conveners. Only when

the Panel had completed a final draft of its report were the parties asked to review and propose edits,

though the suggested edits were limited to concluding whether the report was consistent with the agreed-

upon scope of work as defined in the Terms of Reference and recommending correction of factual points,

as needed. The Conveners were not provided the opportunity to modify the Panel’s conclusions or

question its technical review. On September 22, 2014, the Commission posted the Panel’s Phase I Draft

report on its website for public review.

As a final step of this first phase of this independent review process, the Panel invited public

comments at a meeting convened in Huntington Beach on September 29, 2014 to address relevant

comments on the report. After that meeting, the Panel prepared this final Phase 1 report, which will be

used by a new Panel in the Phase 24 work and which will become part of the Commission’s record for

Poseidon’s upcoming CDP application. Pursuant to the Terms of Reference, all Panel members are joint

authors of the final Phase 1 report, as documented on the signature page of this Report.

Note: During much of this same period, the State was developing a policy meant to help guide

development of seawater desalination and clarify the regulatory requirements for proposed intake and

discharge facilities. Starting in 2007, the State Water Resources Control Board (State Board) convened its

own expert panels and held public workshops and hearings, and in August 2014, released a draft policy

that identifies the proposed performance standards, study methods, mitigation measures, and other

requirements desalination facilities will be required to meet. The State Board anticipates adopting a final

policy later in 2014. Commission staff and Poseidon participated in the policy development, and both

parties believe the Panel’s work is consistent with the approaches anticipated in the draft policy.

4 According to the TOR, Phase 2 of the panel is described as: “Still focused on the Huntington Beach site, the Panel would characterize the technically feasible subsurface intakes identified in Phase 1 relative to a broader range of evaluation criteria, as recommended by the parties and determined by the Panel, such as size, scale, cost, energy use, and characteristics related to site requirements and environmental concerns consistent with the California Coastal Act’s definition of feasible, and as compared to the proposed open intake (Appendix B).”


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_____________________________ MICHAEL KAVANAUGH

iii. Signature Page WE, THE UNDERSIGNED MEMBERS OF THE CCC-POSEIDON PROPOSED HUNTINGTON BEACH DESALINATION FACILITY INDEPENDENT SCIENTIFIC TECHNICAL ADVISORY PANEL, AUTHORED AND HEREBY CONFIRM OUR CONCURRENCE WITH THE FULL TEXT OF THIS PHASE 1 REPORT:

_____________________________

ROBERT BITTNER

_____________________________

MARTIN FEENEY

___________________________ ROBERT MALIVA

_________________________ THOMAS MISSIMER


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iv. Panelists’ Executive Summary a. Introduction The Independent Scientific and Technical Advisory Panel (ISTAP or “Panel”) was established by

an agreement between the California Coastal Commission (CCC or Commission), and Poseidon

Resources (Surfside) LLC (Poseidon) to undertake an independent assessment of the technical feasibility

of using one or more potential subsurface intake technologies to supply the feed water to a seawater

desalination facility using the Sea Water Reverse Osmosis (SWRO) technology. The facility would be

located in Huntington Beach with a presumed hydraulic capacity to meet a goal of producing 50 Million

Gallons per Day (MGD) of potable water. Background on the rationale for establishing the ISTAP

process is provided in the convener’s preface to this report.

The process of establishing the ISTAP and coordinating ISTAP deliberations and preparation of a

Phase 1 consensus technical report is being managed by CONCUR, Inc. (CONCUR), a California firm

specializing in facilitation and mediation processes to resolve complex technical disputes. Under the

direction of CONCUR, the CCC and Poseidon, designated as “Conveners” in this process, jointly selected

five experts on various technical aspects of subsurface intake options. Qualifications for the ISTAP

members are provided in Appendix A. CONCUR established a contract with each Panel member that

defines the scope of work for the feasibility assessment. The structure and operating procedures of the

scientific and technical review and specific charge to the Panelists are defined in the Terms of Reference

(TOR) document jointly developed by Poseidon and the CCC with CONCUR’s assistance prior to

Panelist recruitment (see Appendix B). Additional background on the process is provided in the

convener’s preface.

The full ISTAP assessment of feasibility will be carried out over the course of two or more

phases. The objective of Phase 1 is bounded to examine only the “Technical Feasibility” of subsurface

intakes at or near the proposed site at Huntington Beach, California. For the Phase 1 Report, the working

definition of “Technical Feasibility” was specified in the expert contract documents as: “Able to be built

and operated using currently available methods”. The specific question posed to the ISTAP in Phase 1


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then is: Will any of the currently available subsurface intake designs be technically feasible at the

proposed site at Huntington Beach?

The ISTAP also determined that “Technical Feasibility” should be further defined by generally

recognized factors as documented in the California Coastal Act of 1976. This Act provides the following

definition:

“Feasible” means capable of being accomplished in a successful manner within a

reasonable period of time, taking into account economic, environmental, social, and

technological factors. (Section 30108 of the California Public Resources Code)

Of these four factors, the Phase 1 Assessment focuses primarily on technological factors. The

ISTAP also concluded that the definition of “technical feasibility” should be informed by the recent State

Water Resources Control Board Draft Desalination Policy published July 3, 2014. The Draft Policy

specifies 14 factors, identified in the introduction to this report that should be considered to determine

subsurface intake feasibility. The ISTAP has determined that the following six factors are technological in

nature, namely, (1) geotechnical data for the site, (2) hydrogeology, (3) benthic topography, (4)

oceanographic conditions, (5) impact on freshwater aquifers, and (6) other site and project-specific

factors. These six factors thus comprise the “Technical Factors” considered in this Phase 1 assessment,

consistent with interpretation of the California Coastal Act definition of “Feasible”. Consideration of the

other eight factors identified in the Draft Policy may be incorporated into Phase 2 of the overall Panel

process to assess feasibility of those technologies deemed “Technically Feasible” in the Phase 1

assessment.

b. Approach

The ISTAP has relied upon both technical information provided by the Conveners as well as an

extensive body of published data on all technical considerations for subsurface intake structures

associated with desalination facilities worldwide using the SWRO technology. In addition, the ISTAP

participated in a public meeting held in Huntington Beach, CA on 9-10 June, 2014, which included

presentations by representatives of the conveners and comments from other interested parties. Materials


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presented at this public meeting are available on the CCC website. Subsequently, the ISTAP met in San

Francisco on 28 and 29 July, 2014 to deliberate on the large amount of technical information. On

September 22, the Coastal Commission released the Panel’s Phase 1 Draft Report, and opened the

opportunity for the public to provide comments. On 29 September, 2014, CONCUR convened a public

meeting at the Huntington Beach Main Library. The purpose of the information-sharing meeting was for

the Panel to present its findings and conclusions, offer clarifications where requested, and receive and

consider public comments. Public comments received in writing and verbally as of 3 October, 2014 have

been considered by the ISTAP. After consideration of these comments, the ISTAP has incorporated

appropriate edits in this Final Report.

In preparing this Report, the first step undertaken by the ISTAP was to identify all possible

subsurface intake options that have at least one application of the technology worldwide for the purposes

of delivering water from a surface source regardless of economic considerations, or the other factors

identified in the California Coastal Act definition of feasibility. These purposes could include not just

intakes for desalination plants, but also any subsurface intake technology used to obtain fresh, brackish or

saline water from a surface water body. The ISTAP considered that these technical options would be

considered as “currently available methods”.

The ISTAP then established a list of criteria and subfactors that address all of the technical factors

noted above. Information was then developed, based on technical information available to the ISTAP or

using professional judgment, to address all technical factors for each of the selected subsurface intake

options. The matrix developed through this process then served as the foundation of the ISTAP’s

determination as to whether or not any of the options were feasible based on technological factors solely.

In simple terms, this means that cost and other factors normally considered under the California Coastal

Act definition of feasible were not addressed in Phase 1 of the assessment.

c. Site and Project Description

The proposed location of the desalination facility is a 12-acre site inshore of the Pacific Coast

Highway, five to ten feet above mean sea level (MSL), adjacent to AES Huntington Beach generating


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station, approximately two miles south of the Huntington Beach (HB) Municipal Pier, and one mile north

of the mouth of the Santa Anna River. The site has an existing 1,800-ft long seawater surface intake that

is being used to bring cooling water into the power plant and a 1,500-ft outfall used to discharge the water

back to the sea. The beach area that fronts the proposed site is designated for “Public” or “Semi-Public”

use. The HB State and City Beaches see more than eight million beach goers annually. The proposed site

is adjacent to the Huntington Beach Wetlands Conservancy. The closest ocean Marine Protected Areas

(MPAs) to the proposed site are the inlet to the Bolsa Chica estuarine/wetlands complex about three miles

north and Crystal Cove, eight miles south of the proposed desalination facility site.

The proposed project site is located on the southwest (SW) edge of the Orange County Water

District, which pumps 70% of the water demand for 2.4-million people from 200 wells in Orange County.

The proposed site overlies the western portion of the Talbert aquifer, which is a significant groundwater

source for Orange County’s water needs. The Talbert aquifer is a confined aquifer that extends and

outcrops on the seafloor. As the result of a reversed seaward gradient, seawater intrusion has occurred at

the coast and threatens inland portions of the aquifer system. Orange County injects 30 MGD of treated

wastewater into the aquifer system to replenish the basin and control seawater intrusion.

The proposed facility is in close proximity, about five miles, from the regional water delivery

system, and Poseidon’s intent is to construct a pipeline to use this existing distribution system for

acceptance of product water from the desalination facility. Several active faults run parallel to the

shoreline, underlie the proposed site, and intersect the Talbert aquifer. These faults pose an earthquake

risk that could cause liquefaction and settlement at the facility. The shore near the site is a high-energy

zone, characterized by large swells and ocean currents. The nearshore seabed in front of the proposed site

is subject to seasonal changes due to wave erosion and seasonal equilibrium changes. As a result, the

inshore sediment cover is subject to large-scale seasonal bottom profile changes.

Although Poseidon has withdrawn their permit application at this time, the ISTAP has assumed

that the initial permit application and subsequent response by the Coastal Commission staff (Staff Report

on Poseidon Application, 10 October, 2013, E-06-007) defines the likely attributes of a future permit


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application pending the outcome of this assessment process. Thus, the ISTAP considered that each

subsurface intake technology would need to be capable of withdrawing 100 to 127 million gallons per day

(MGD), the hydraulic capacity needed to meet a production goal of 50 MGD using the SWRO

desalination technology. The maximum capacity of 127 MGD was determined by Poseidon to meet

concentrate water quality discharge standards in the receiving waters, using 27 MGD to dilute the

concentrate from the desalination process with discharge of the diluted concentrate through a

conventional outfall design. The lower hydraulic capacity of 100 MGD would still be sufficient to meet

the production goal of 50 MGD of potable water. Under this scenario, concentrate disposal would be

conducted through appropriately designed diffuser outfalls to meet the water quality discharge standards.

d. Findings

The ISTAP evaluated nine types of subsurface intakes for technical feasibility at the Huntington

Beach site. These subsurface intake options included: (1) vertical wells completed in the shallow aquifer

above the Talbert aquifer, (2) vertical deep wells completed within the Talbert aquifer, (3) vertical wells

open to both the shallow and Talbert aquifers, (4) radial collector wells tapping the shallow aquifer, (5)

slant wells tapping the Talbert aquifer, (6) seabed infiltration gallery (SIG), (7) beach gallery (surf zone

infiltration gallery)5, (8) horizontal directional drilled wells, and (9) a water tunnel. The evaluation of the

technical feasibility of each of these options, based on analysis of numerous technical factors is presented

in Table 5.1. A condensed version of this matrix is shown below in Table ES-1. This evaluation by the

ISTAP was based on the hydrogeologic and oceanographic conditions specific to the proposed

Huntington Beach AES site and proximate areas. The technical infeasibility of a particular intake

technology at this location should not be generalized to feasibility considerations of any intake type in

different settings or locations.

5 The ISTAP uses the terms “surf zone gallery” and “beach gallery” interchangeably in this Report.

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Subfactor

Vertical wells completed

above confining unit

Vertical wells completed below

confining unit


above and below confining unit

Radial collector in shallow

aquifer

Slant Wells completed in

Talbert aquifer

Engineered seafloor

infiltration gallery

Surf zone infiltration

gallery

HDD wells in shallow aquifer Water tunnel

HydrogeologyImpact on fresh water aquifers Yes Yes Yes No Yes No No No No

Design ConstraintsPerformance risk - degree of uncertainty of outcome

Low Low Low Medium Medium Medium Medium High Unknown

OceanographicSensitivity to sea level rise High High High High Medium Low Low Low Low

GeochemistryRisk of adverse fluid mixing Low High High Low High Low Low Unknown Low

Precedent on large scale in similar geological conditions

Jeddah, Saudi Arabia; 5 MGD from 10 wells

No precedent No precedent

Pemex system in Mexico, 3 collectors with total capacity of 12 Mgd

No precedentFukuoka, Japan. 27 MGD intake capacity

No precedent

Alicante, Spain; designed for 34 MGD, operating at 17 MGD

Alicante, Spain, 17 MGD

Key considerations / fatal flaw(s)

Performance risk: inadequate aquifer capacity and great drawdowns. Low yields would require extremely high number of wells, major water quality risk

Complications with seawater intrusion management and production from Orange Groundwater Basin


High performance risk due to inappropriate geologic conditions

Complications with seawater intrusion management and production from Orange Groundwater Basin; geochemical impacts

Construction complexity

Construction complexity in high energy environment, potential restrictions on allowable construction times/beach closure, impacts of beach renourishment

Performance risk concerns over granular materials and maintenance of well performance

Complex construction involving ground freezing. High performance risk - no precedence for project scale. Cost likely prohibitive

Technically Feasible? Y or N N N N N N Y Y N N

Table ES-1- Subsurface Intake Summary Matrix


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The ISTAP carefully evaluated fatal flaws of each subsurface intake type considered for

application at Huntington Beach. Only the seabed infiltration gallery and the surf zone (beach)

gallery survived the fatal flaw analysis, and both are deemed technically feasible. Both gallery

types would face constructability challenges related to subsea construction. The surf zone gallery

was judged to have particularly challenging construction issues (and thus a lesser degree of

technical feasibility) related to construction in a high-energy environment. The ISTAP does not

consider the existing scale of use of any particular subsurface intake compared to the capacity

requirement at Huntington Beach to be a fatal flaw for technical feasibility (e.g., the only existing

seabed infiltration gallery has a capacity of 27 MGD compared to the lower hydraulic capacity of

100 MGD required for the proposed Huntington Beach project, and no large scale implementation

of a beach gallery has been constructed and operated as of September 2014).

The Panel interpreted its charge relative to the Terms of Reference to be the evaluation of

the technical feasibility of subsurface intake technologies linked to the scale of a likely project

proposal. Consistent with that approach, the Phase 1 Panel considered nine technologies keyed to

a potential project with hydraulic capacity in the range 100 to 127 MGD. The Panel did address

the broad issue of downward scalability where it saw relevance, but did not consider a full or

parsed range of scale options for any of the nine technologies, as doing so would have exceeded

the agreed-upon scope of work defined in the TOR. Scalability issues could be addressed in

subsequent assessments of other feasibility factors at the discretion of the Conveners.

It is the collective opinion of the ISTAP that each of the other seven subsurface intake

options for the target hydraulic capacity range (100-127 MGD) had at least one technical fatal

flaw that eliminated it from further technical consideration. The shallow vertical wells would

create unacceptable water level drawdowns landward of the shoreline and could impact wetlands

and cause movement of potential contaminants seaward. The deep vertical wells would have a

significant impact on the Talbert aquifer that would interfere with the management of the salinity

barrier and the management of the interior freshwater basin. The combined shallow and deep-


18

water wells would adversely impact both the shallow aquifer and Talbert aquifer, and in addition,

would produce waters with differing inorganic chemistry, which would adversely affect SWRO

plant operation. Radial collector wells constructed into the shallow aquifer would have to be

located very close to the surf zone which would make them susceptible to damage during storms

and would be impacted by the projected sea level rise. Slant wells tapping the Talbert aquifer

would interfere with the management of the salinity barrier and the management of the freshwater

basin, and further, would likely have geochemical issues with the water produced from the

aquifer (e.g., oxidation states of mixing waters). A water tunnel constructed in the unlithified

sediment at Huntington Beach would have overwhelming constructability issues.

e. Recommendations

The ISTAP recommends that consideration be given solely to seabed infiltration galleries

(SIG) and beach gallery intake systems in the Phase 2 assessment. As noted, the ISTAP was not

asked to evaluate the economic considerations of using a subsurface intake versus a conventional

open-ocean intake during Phase 1 of the assessment. The ISTAP recommends that in the next

phase, the Panel should focus primarily on the constructability of the seabed infiltration and

beach gallery intake systems, because this greatly affects the economic viability of their potential

use. Other factors should be considered consistent with the definition of “feasibility” in the

California Coastal Act.

However, the ISTAP recommends that in the Phase 2 evaluation of the subsurface intake

options, a detailed lifecycle cost analysis should be provided to the succeeding committee. This

lifecycle cost analysis should contain at least four scenarios, including:

1) the lifecycle cost over an appropriate operating period obtaining the feed water from

a conventional open-ocean intake without considering the cost of potential

environmental impact of impingement and entrainment,


19

2) the lifecycle cost over an appropriate operating period obtaining feed water from a

conventional open-ocean intake considering the cost of potential environmental

impact of impingement and entrainment,


a seabed gallery intake system (or beach gallery intake system) using the same

pretreatment design as used in treating open-ocean seawater, and


a seabed gallery intake system (or beach gallery intake system) using a reduced

degree of pretreatment, such as mixed media filtration and entry into the cartridge

filters.

In each of these scenarios, the ISTAP recommends that the selected design hydraulic

capacity match both the minimum and maximum flow rates consistent with the desired

production rate of a 50 MGD desalination facility using the SWRO technology. The definition of

an “appropriate” operating period should follow accepted industry standards for such lifecycle

cost analyses. Typically, a period of 30 years is used, but given concerns on the potential for sea

level rise impacts, analysis over a longer operating period (e.g. 50 years) may be desirable. In

addition, the ISTAP questions the need for the use of seawater to dilute the concentrate discharge

given the well-known use of diffuser outfalls to meet ocean discharge requirements.

The ISTAP also recommends that the Phase 2 Panel continue to rely on the definition of

“Technical Feasibility” as defined by generally recognized factors as documented in the

California Coastal Act of 1976 (Section 30108 of the California Public Resources Code)

Chapter I. INTRODUCTION Poseidon Resources (Surfside) LLC (Poseidon) has proposed construction of a seawater

desalination facility using the Sea Water Reverse Osmosis (SWRO) technology in Huntington

Beach, California. The California Coastal Commission (CCC or the Commission) acting under


20

the California Coastal Act is responsible for review and approval of the permit application for

such facilities. Poseidon’s permit application proposed the use of an existing open ocean intake

for supply of feed seawater to the facility. However, it has been reported that open ocean intakes

can cause unacceptable levels of impingement and entrainment of marine life and have the

potential for degrading the local or regional marine ecosystem(s). Because of these concerns, the

CCC recommended that Poseidon work with CCC staff to conduct an independent assessment of

the feasibility of using subsurface intake technology, with the intention of reducing ecological

impacts while still providing a sufficient volume of feed water to the proposed facility.

As a result of this request, Poseidon has temporarily withdrawn the permit application

and, with the assistance of CONCUR, has worked with the CCC to form the ISTAP for the

express purpose of preparing a concise summary of the technical feasibility of using one or more

potential subsurface intake systems for supplying feed water to the proposed Huntington Beach

seawater desalination facility (See the convener’s preface for the background in establishing the

ISTAP process). The specific question to be answered by the ISTAP is: Will any of the several

potential subsurface intake designs be technically feasible at the proposed site at Huntington

Beach?

CONCUR, CCC, and Poseidon have provided the ISTAP with a wide range of technical

information regarding the proposed desalination facility, including specific information on the

characterization of the geophysical, hydrological, and geochemical features of the proposed site.

However, the aim of CCC and Poseidon has been to conduct an independent scientific fact -

finding and review process where the findings and conclusions of the assessment are completed

without intervention from CONCUR, CCC or Poseidon. In addition, the ISTAP has not relied

solely on the information provided by CONCUR, CCC or Poseidon but has conducted its own

search for published literature, relevant case study reports, and available on-site studies of similar

or comparable SWRO desalination facilities around the world. For a listing of the documents

reviewed by the ISTAP please see Chapter VII of this report – Reports on Subsurface Intakes.


21

The following brief summary of the proposed project and a site description was

developed from information provided to the Panel.

1.1 General The selected location of the proposed desalination facility is a 12-acre site inshore of the

Pacific Coast Highway, five to ten feet above MSL, adjacent to AES Huntington Beach

generating station, approximately two miles south of the Huntington Beach Municipal Pier, and

one mile north of the mouth of the Santa Anna River. The site has an existing 1,800-ft long

seawater intake previously used to bring cooling water into the power plant and 1,500-ft outfall

used to return the water. The beach area that fronts the proposed site is designated for “Public” or

“Semi-Public” use. The Huntington Beach State and City Beaches see more than eight million

beach goers annually.

1.2 Environmental

The proposed site is adjacent to Huntington Beach Wetlands Conservancy. The closest ocean

Marine Protected Areas (MPAs) to the proposed site are the inlet to the Bolsa Chica

estuarine/wetlands complex about three miles north and Crystal Cove, eight miles south of the

proposed desalination facility site.

1.3 Economical The proposed facility is about five miles from the regional potable water delivery system

operated by the Municipal Water District of Orange County and other water utilities, and the

intent is for Poseidon to construct a pipeline to this existing distribution system for distribution of

the output of the facility.


22

1.4 Hydrological

The proposed project site is located on the SW edge of the Municipal Water District of

Orange County, which pumps 70% of the water demand for 2.4-million people from 200 wells in

Orange County. The proposed site overlies the western portion of the Talbert aquifer, which is a

significant water supply source for Orange County’s water needs. The Talbert aquifer is a

confined aquifer that extends and outcrops on the seafloor. As the result of a reversed seaward

gradient, seawater intrusion has occurred at the coast and threatens inland portions of the aquifer

system. Orange County injects 30 MGD of highly treated reclaimed wastewater into the aquifer

system to replenish the basin and control seawater intrusion.

1.5 Seismic activity

Several active faults run parallel to the shoreline, underlie the proposed site, and intersect

the Talbert aquifer. These faults pose a risk of liquefaction and settlement at the facility.

1.6 Oceanographic setting

The nearshore area of the site is a high-energy zone, characterized by large swells and

ocean currents. In the neighborhood of the Huntington Beach, average incident wave heights of

between 0.9 m and 1.2 m prevail 87% of the time during a typical year in an El Niño-dominated

climate period. This wave height range occurs primarily during the spring, summer and fall

seasonal periods. During the remaining 13% of the time (primarily during winter months),

average incident wave heights near the Huntington Beach increase to 2.4 m to 2.7 m, with some

waves reaching significant heights as large as 4 m to 6 m.

The nearshore seabed in front of the proposed site is subject to seasonal changes due to

wave erosion and seasonal equilibrium changes. As a result, the inshore sediment cover is subject

to large-scale seasonal bottom profile changes.


23

1.7 Constructability

The high-energy surf zone environment off Huntington Beach prevents the use of

conventional floating construction equipment and necessitates the use of access trestles or

elevated bridging structures built out from shore to allow construction cranes and personnel to

safely travel and work above the waves. This method of construction is extremely slow and

expensive.

To provide clarity of purpose in preparing this concise short report, the definition of

“feasible” has been taken from California Coastal Act of 1976 Definitions § 30108.

FEASIBLE

“Feasible” means capable of being accomplished in a successful manner within a

reasonable period of time, taking into account economic, environmental, social, and

technological factors.

The State Water Resources Control Board Draft Desalination Policy published July 3rd

2014 states the following factors should be considered to determine subsurface intake feasibility:

1. Geotechnical data 8. Local water supply and existing users

2. Hydrogeology 9. Desalinated water conveyance

3. Benthic topography 10. Existing infrastructure

4. Oceanographic conditions 11. Co-location with sources of dilution water

5. Presence of sensitive habitats 12. Design constraints (engineering, constructability)

6. Energy use 13. Project lifecycle costs

7. Impact on freshwater aquifers 14. Other site- and factory-specific factors

This independent review is structured in two Phases. The objective in Phase 1 is to

examine the “Technical Feasibility” of subsurface intakes at or near the proposed Huntington

Beach site. For the Phase 1 report, the TOR’s working definition of “Technical Feasibility” is:


24

“Able to be built and operated using currently available methods”. For this Phase 1 report, ISTAP

has considered six of the above listed criteria: 1, 2, 3, 4, 7, and 12 as relevant to technical

considerations for a feasibility assessment. The Phase 2 ISTAP Report may consider, among

other issues, the remaining criteria: 5, 6, 8, 9, 10, 11, 13 and 14.


25

Chapter II. APPROACH 2.1 Introduction The ISTAP conducted this analysis of the technical feasibility of subsurface intake

options under the guidance of the Coastal Commission staff and the Project Advocate, Poseidon,

who established the Terms of Reference (TOR) for Panel members that describes in general terms

the procedures to be followed by the ISTAP members. The main deliverable from the ISTAP is

this Phase 1 Report (Report) detailing the deliberations, findings and conclusions of the ISTAP. A

public meeting was held in Huntington Beach on 9-10 June 2014, and documentation on the

meeting agenda and presentations are available online (http://ftp.coastal.ca.gov6). Subsequently,

the ISTAP met in San Francisco on 28-29 July, 2014 to deliberate on the large amount of

technical information provided both at the public meeting as well as information made available

via the Coastal Commission website. On September 22, the Coastal Commission released the

Panel’s Phase 1 Draft Report, and opened the opportunity for the public to provide comments. On

29 September 29, 2014, the CONCUR convened a public meeting at the Huntington Beach Main

Library. The purpose of the information-sharing meeting was for the Panel to present its findings

and conclusions, offer clarifications where requested, and receive and consider public comments.

Public comments received in writing and verbally as of 3 October, 2014 have been considered by

the ISTAP. After consideration of these comments, the ISTAP has incorporated appropriate edits

in this Final Report.

6 To access the ISTAP meeting information, go to http://ftp.coastal.ca.gov, then go to General Public folder, enter user name: public, password: ocean03. Then select the Expert Panel Public Review folder.


26

This section of the report provides a brief summary of the approach used by the ISTAP to

address the principal question addressed to the ISTAP, namely, is there a “technically feasible”

subsurface intake option that “is able to be built and operated using currently available methods?”

The ISTAP relied upon the definition of “technically feasible” established under the

California Coastal Act in 1976 in considering the feasibility of subsurface intake options. This

definition defines four factors to be considered in determining the feasibility of a project. The

ISTAP agreed that in Phase 1 of the study, the exclusive focus would be on the “technological”

factors, with a possible Phase 2 study to address issues associated with the other three factors.

Thus, the ISTAP considered all possible subsurface intake options that have at least one

application of the technology worldwide for the purposes of delivering water from a surface

source regardless of economic considerations, or the other factors identified under the California

Coastal Act definition. These purposes could include not just intakes for desalination plants, but

also any subsurface intake technology used to obtain fresh, brackish or saline water from a

surface water body. The ISTAP considered that these technical options would be considered as

“currently available methods”.

With this definition agreed to by all ISTAP members, a wide range of technologies were

considered as potentially technically feasible options for the Huntington Beach Desalination

Project (Project). One initial challenge in this approach was the specification of the Project design

attributes, particularly the desired maximum hydraulic capacity of the proposed Project needed to

meet the proposed goal of producing 50 MGD of potable water.

Although Poseidon has withdrawn their permit application at this time, the ISTAP has

assumed that the initial permit application and subsequent response by the Coastal Commission

staff (Staff Report on Poseidon Application, 10 October, 2013, E-06-007) defines the likely

attributes of a future permit application pending the outcome of this Panel Process. The ISTAP

considered subsurface intake technologies that would be capable of producing 100 to 127 million

gallons per day (MGD), the hydraulic capacity needed to meet a production goal of 50 MGD


27

using the SWRO desalination technology. The maximum capacity of 127 MGD was determined

by Poseidon to meet water quality discharge standards, using 27 MGD to dilute the concentrate

from the SWRO desalination process. The lower capacity of 100 MGD would be sufficient to

meet the desired hydraulic performance of the proposed Project.

2.2 Potential technologies that meet hydraulic capacity goals During the San Francisco meeting, the ISTAP conducted a screening analysis to

determine the technical feasibility of a wide range of subsurface intake technologies. In addition

to the technologies discussed during the Public Meeting in June, the ISTAP also considered other

options known to the Panel members based on experience and knowledge of the literature on

subsurface intake structures, some of which was written by Panel members. The nine options

considered by the ISTAP in the screening analysis are listed below:

1) Vertical wells completed in the shallow aquifer above the Talbert aquifer upper confining

unit

2) Vertical wells completed in the Talbert aquifer (below confining unit)

3) Vertical wells completed above and below confining unit

4) Radial (Ranney) collector wells in the shallow aquifer

5) Slant wells completed in the Talbert aquifer

6) Engineered seafloor infiltration gallery

7) Surf zone (beach) infiltration galleries

8) Horizontal directional-drilled (HDD) wells underneath the sea floor.

9) Water tunnels.

The ISTAP then established the factors to be used in the screening analysis. As discussed, the

primary technical factors, derived in part from the State Water Resources Control Board Draft

2014 Desalination policy included the following:

• Hydrogeology


28

• Design constraints

• Oceanographic conditions (including benthic features)

• Geochemistry.

In addition, the ISTAP considered two precedence questions, namely, (a) has the

technology been successfully implemented in geologic conditions similar to those expected to be

encountered at the Huntington Beach site and (b) has the technology been successfully

implemented at a large scale in similar geologic conditions? The ISTAP considers “large scale” to

be greater than 10 MGD.

For each of these general factors, the ISTAP considered a series of qualitative and

quantitative subfactors that characterize the technical features of each of the screened

technologies, including whether or not a technology suffered from a “fatal” flaw that would

eliminate that option from further consideration. Details of these subfactors, their relevance to the

decision on technical feasibility, and what constitutes a “fatal” flaw are presented later in this

Report. Following a thorough screening-level consideration of all the subfactors, as applied to

each of the nine technologies considered, the ISTAP then deliberated as to whether or not a

technology was: (a) technically feasible or (b) not technically feasible. It should be stressed again

that cost was not a factor in screening the nine technologies. Furthermore, the evaluation

performed was based on the hydrogeologic and oceanographic conditions specific to the

Huntington Beach AES site and proximate areas. The infeasibility of a particular intake type at

this location should not be construed as indicating the ISTAP’s conclusion that this intake type is

not feasible in a different setting or location.


29

Chapter III. Subsurface Intake Options Considered 3.1 Introduction Subsurface intake systems have been successfully used at numerous global locations to

provide feed water to SWRO water treatment facilities (Missimer, 2009; Missimer et al., 2013).

The predominant type of subsurface intake used is vertical wells, but they are most commonly

used to supply small (<10,000 m3/d; <2.6 MGD) to medium (10,000-50,000 m3/d; 2.6-13.2

MGD) capacity SWRO plants. Gallery systems are a relatively new class of subsurface intake

systems. Beach galleries (referred to herein as either “beach galleries” or “surf zone galleries”)

were introduced by Missimer and Horvath (1991), Missimer (2009), and Maliva and Missimer

(2010). These intakes use a gallery system underlying the intertidal surf zone (Maliva and

Missimer, 2010). Seabed galleries are constructed offshore in the seabed and act similar to a slow

sand filter (Crittenden et al, 2005; Missimer, 2009).

Additional innovations in SWRO systems are being developed in different parts of the

world. A tunnel intake system was designed and constructed at Alicante, Spain (Rachman et al.,

2014). This system produces water from a horizontal tunnel that contains lateral screens, similar

in concept to a Ranney well. Other systems, such as landward excavations filled with rock and

artificial marine filter structures, are also being developed.

There are several reasons why subsurface intake systems are used instead of open-ocean

intake types. The primary benefits of subsurface intakes are reductions of possible environmental

impacts associated with impingement and entrainment, chemical usage required for pretreatment

prior to the RO system, the complexity of in-plant pretreatment processes, and overall SWRO

costs, particularly operational costs (Wright and Missimer, 1997; Missimer et al., 2010; Missimer

et al., 2013). Additionally, several provisions of California state policies require that entrainment

effects be minimized to the extent feasible, which generally requires that subsurface intake


30

methods be assessed as part of environmental and permit review of proposed desalination

projects.

The key challenge in the design of subsurface intakes for SWRO facilities is that the technical

feasibility of using a given type is site-specific, based on local hydrogeologic and oceanographic

conditions. There are limits on the yield of various modular units, such as a single well or a single

gallery cell.

3.2 Hydrogeology of the Huntington Beach area The project area lies on the coastal edge of the Orange County Groundwater Basin. The

hydrogeologic setting has been discussed in detail in several of the references cited (Herndon and

Bonsangue, 2006, and others) and will not be repeated in this document. Briefly, the nearshore

area of Huntington Beach is underlain by a sequence of Holocene and Pleistocene sediments to a

depth of approximately 200 feet. These materials mostly constitute the coastal extension of the

Talbert aquifer. The thickness of the aquifer decreases seawards as a result of uplift along the

Newport-Inglewood Fault. Non-water-bearing consolidated materials have been uplifted on the

south side of the fault, reducing the aquifer thickness. In addition to reducing overall aquifer

thickness at the coast, movement along the fault has elevated non-water-bearing materials7 above

current sea level, creating natural barriers to groundwater flow. The so-called “Talbert Gap”,

located just inland from Huntington Beach, is a subsurface erosional feature in this uplifted block

that connects the coastal portion of the basin with the inland portion. A diagrammatical

explanation of the Basin is presented below.

7 Non-water-bearing materials are typically fine-grained sediments or consolidated rocks that do not transmit water easily.


31

Figure 3.1. Hydrogeologic section from the Pacific Ocean through the Talbert Gap into the basin (from the Orange County Water Groundwater Master Plan and Edwards et al., 2009) The Talbert aquifer has been impacted by seawater intrusion. Inland extractions have

lowered water levels significantly below sea level and reversed the seaward gradient such that

seawater now moves inland toward and through the Talbert Gap and threatens the water quality in

the thicker portion of the groundwater basin north of the Newport-Inglewood Fault. Local water

management agencies have instituted management efforts to control seawater intrusion into the

inland portion of the basin by raising groundwater levels within the Talbert Gap with injection

wells.

Based on exploratory work performed by Psomas (2011), GeoSyntec (2013) and others,

the localized generalized sequence of sediments in the project area consists of shallow silty-sand

deposits to a depth of approximately 70 feet where a 10- to 20-foot thick finer-grained layer is

encountered. This finer-grained layer constitutes the aquitard that overlies the sand, gravel and

clay deposits that comprise the Talbert aquifer. The base of the Talbert aquifer is at a depth of

!Project Site "


32

approximately 200 feet. Groundwater occurs under unconfined conditions in the geologic

materials above the aquitard, and confined conditions in materials below the aquitard.

3.3 Well intake systems 3.3.1 Introduction Globally, the highest capacity subsurface intakes using wells for a SWRO facility are

located at Sur, Oman (42.2 MDG), Tordera at Blanes, Spain (33.8 MGD), Pembroke, Malta (31.7

MGD), and Bajo Almanzora, Mallorca, Spain (31.7 MGD) (David et al., 2009; Missimer et al.,

2013). Very large capacity Ranney well systems are used in the United States as intakes of

freshwater along rivers (Missimer, 2009). All of these seawater facilities use conventional vertical

wells that are constructed in high permeability limestone aquifers. These geologic settings in

consolidated strata contrast with the unconsolidated materials at the proposed project site in

Huntington Beach. The largest capacity vertical well intake systems that produce from unlithified,

siliciclastic aquifers are located in Saudi Arabia along the coast of the Red Sea (Al-Mashharawi

et al., 2014). A large number of smaller capacity systems have been documented globally

(Schwartz, 2000, 2003; Voutchkov, 2005; Bartek et al., 2012). These facilities have a maximum

capacity of up to about 15 MGD (Al-Mashharawi et al., 2014; Dehwah et al., 2014).

3.3.2 Vertical wells completed above upper confining unit Although not specifically presented as a potential source for this project, this possibility

is included because this source has precedent in California. The wells would be less than 100 feet

in depth and would be designed to produce from shallow sediments above the aquitard and in

direct hydraulic continuity with the ocean.

Shallow wells producing from beach deposits have been used to supply feedwater for

small desalination facilities worldwide. Wells producing from beach deposits typically provide


33

high-quality water with SDI8 values less than 2. In California, Marina Coast Water District

operated a beach well to supply their desalination facility in the 1990's. This well was

approximately 60 feet deep, produced from medium-grained sand, and had a production rate of

approximately 400 gpm (Fugro 1995). The currently operating desalination facility in Sand City,

California uses shallow (approximately 60 feet in depth) beach wells to provide feed water for the

small (~ 0.3 MGD) facility. The beach sands at Sand City are finer grained than Marina.

The ultimate yield of any well source would be dependent on the number of wells; the

number of wells is a function of the location of the wells, the spacing of the wells and the

materials from which they produce. In general, water produced from beach wells would be

derived from both inland and offshore sources - the ratio between these sources again being a

function of the location and the hydrogeologic setting.

Figure 3.2. Conceptual diagram of the beach well (from Missimer et al., 2013). 3.3.3 Vertical wells completed below confining unit Deep vertical wells completed in the Talbert aquifer was formally discussed and

evaluated by Poseidon (Psomas 2011, Geosyntec, 2013). These wells would be perforated below

8 SDI is an abbreviation for Silt Density Index. This is a parameter used by membrane manufacturers and consultants to determine the potential for membrane fouling. It is commonly used in SWRO plant design, especially for pretreatment systems.


34

the regional aquitard. The source of the produced water would be a blend of native ground water,

induced vertical leakage from the ocean, and horizontal flow from the outcrop of the sediments

that comprise the Talbert aquifer on the seafloor. The blend would be a function of the distance to

the subsea outcrop and the vertical leakage through the aquitard.

The yield per well would be a function of aquifer transmissivity and well spacing (which

controls interference between wells). The per-well yield advanced by Poseidon is 1.2 MGD per

well, an estimate that appears reasonable for the materials. The per-well yield is less sensitive to

setback from the ocean than shallow wells – however, water quality in the blend would have

some sensitivity to the distance from the ocean. Extractions from the confined Talbert aquifer

would have on-land drawdown impacts. These drawdown impacts would complicate seawater

intrusion management efforts and could have undesirable impacts on coastal wetlands

(Geosyntec, 2013).

3.3.4 Vertical wells completed above and below confining unit Another subsurface option would be a supply developed utilizing vertical wells that

produce from both the shallow and the Talbert aquifers. No data was provided by Poseidon on

this option. This could be in the form of individual wells that are perforated in, and produce from,

both aquifer systems or co-located well couplets of two wells, one producing from the shallow the

other from the deeper aquifer. This later concept would avoid the complications of

interconnection of the aquifer systems and would allow capitalization on the infrastructural

investment (power, access road, piping, etc.) in each well location.

Individual dual-perforated well or well couplet yields, depending on the actual materials,

could be approximately that of the summation of the two estimated yields, or approximately 2

MGD per installation. However, whereas the multi-aquifer wells or well couplets could increase

per-installation yields, the on-land drawdown impacts associated with extractions from the

Talbert aquifer would be unmitigated.


35

3.3.5 Radial collector in shallow aquifer A collector well consists of a large diameter (typically 18 feet) caisson from which lateral

perforated spokes are advanced out from the caisson toward or under a proximate water body

(Figure 3.3). Collector wells have been used for the development of drinking water sources from

rivers in the United States for over 80 years. Typical installation involves advancement of 200- to

300-foot-long laterals into the coarse gravels underlying riverbeds. In these geologic settings,

discharge rates of 10 to 15 MGD per collector well can be achieved. Collector wells have also

been used for production of seawater. However, the experience using them is more limited, and

because materials are finer-grained, per-well yields are significantly lower.

The construction of a collector well has an advantage over conventional vertical wells in

that the location of the structure that contains pumping equipment is offset from the location of

the source of water by the length of the lateral. The yields are significantly higher than

conventional wells because the effective radius of the well can be measured in tens of feet rather

than in inches.

Figure 3.3. Conceptual diagram of the collector well (from Missimer et al., 2013). For the subject project, collector well yields of 5 MGD have been suggested by Poseidon.

Given the materials described and the hydrogeologic setting, this estimate appears reasonable.


36

Based on the information provided by Poseidon, it appears that this estimate was based on

collector wells that would produce from the Talbert aquifer. A more appropriate target aquifer for

this technology might be the shallow aquifer - that is, the materials above the confining layer.

However, given the finer-grained materials and reduced available drawdown in the shallow

aquifer, yields from collector wells would likely be lower.

The largest capacity SWRO intake system is located at the PEMEX Salina Cruz Refinery,

Mexico with three wells of 4 MGD each, yielding a total capacity of about 12 MGD (Voutchkov,

2005). This is consistent with the assessment and design work performed by Staal, Gardner and

Dunne/Ranney Corporation (Staal, Gardner and Dunne, 1992) in Marina, California that

suggested a per-well yield of 4 MGD for collectors producing from the shallow beach sands.

3.3.6 Slant wells completed in shallow aquifer Advancing drilling technology has allowed the construction of conventional wells at an

angle (Figure 3.4). Although it is believed that angles as small as 10 degrees from horizontal can

be achieved, the sole successful well was drilled at an angle of 22 degrees in Dana Point,

California (USBR, 2009, GeoScience, 2012). The ability to construct wells at an angle allows the

perforated portion of the well to be placed closer or under an adjacent water body to more

effectively induce vertical flow through the overlying beach sands from this water body into the

well. The amount of flow derived directly from the overlying water body is a function of the

depth of cover and the vertical hydraulic conductivity of the overlying materials.


37

Figure 3.4. Conceptual diagram of the slant well (from Missimer et al., 2013). Analysis presented by Poseidon suggested that to produce the required 127 MGD, as

many as twelve three-well pods producing 12.9 MGD each would be required at a spacing of 600

feet. A separate analysis of the feasibility of the slant wells was performed by Geosyntec (2013).

This analysis estimated that each well could produce 2200 gpm, 40 wells would be needed, and

three miles of beachfront would be required to produce the required 127 MGD.

Only one slant well has been successfully constructed to date, although a major

installation to provide 20 MGD of feedwater capacity is under consideration in the Monterey Bay

area. The successfully completed well is at Dana Point. When it was built and tested in 2006, it

was test pumped at 2000 gpm and displayed a well efficiency of 95%. Recent longer term testing

of the completed test well in 2012 documents the reduction in well efficiency from the original

value of 95% in 2006 to 52% in 2012 (GeoScience 2012). Given this observed reduction in

efficiency over a short period, the long-term performance of the technology has yet to be

confirmed.


38

Assuming the slant wells would be constructed at a 22-degree angle, and are located 100

feet inland from the shoreline, the end of the perforated portion of the slant well will be at least

150 feet below the seafloor. As considered, extractions will be from the Talbert aquifer system

with previously noted inland drawdown impacts.

3.3.7 Horizontal directionally drilled (HDD) wells underneath the sea floor HDD wells are directionally drilled borings that would be drilled from a common

location on the shoreline (Figure 3.5). The boreholes would fan out at a shallow distance under

the seafloor and then exit the seafloor at a distance offshore where a permeable flexible casing

would be pulled back from the ocean location into the borehole. Feedwater would be derived

from the ocean through vertical infiltration through the seafloor. The productivity of the wells is

the function of the permeability of the overlying sediments comprising the seafloor. This

approach has been used with some success in the desalination facility in Alicante, Spain. This

HDD array was originally sized for 45 MGD. However, actual performance has been lower and

water quality problems have occurred (Rachman et al., 2014).

Figure 3.5. Conceptual diagram of the HDD wells at Huntington Beach (from Neodren, 2014).


39

Preliminary analysis by of the project in Alicante, Spain for Poseidon suggests that the

required 127 MGD of feedwater could be provided by 60 wells in two fans of 30 wells. However,

after receipt of the recent hydraulic conductivity values from the vibracore samples, this estimate

(provided by Poseidon) was reported to range between 84 and 231 wells contained in three to

eight fans.

3.4 Gallery intake systems 3.4.1 Introduction Gallery intake systems are designed based on the concept of slow sand filtration.

However, there are differences in how the gallery intake systems function within the seawater

environment. In freshwater sources, such as a river, a surface film forms on slow sand filters,

called the “schmutzdecke” (i.e., dirty layer in German), which is biologically active and is a key

part of the treatment process (Huisman and Wood, 1974; Crittenden et al., 2005; Hendricks,

2001, 2011). Slow sand filters have a long history of successful operation for treatment of water

for potable purposes worldwide, beginning in the early 1900s. As a result of the bio-active layer

formation, most of the reduction of water constituents that require removal prior to RO treatment

occurs within the upper few inches of the filter surface. In seawater gallery systems, this upper

layer does not form, and therefore, the treatment occurs throughout the uppermost two to six feet

of the gallery (unpublished research conducted at the King Abdullah University of Science and

Technology, Saudi Arabia [2014]).

3.4.2 Surf zone infiltration galleries Beach (surf zone) gallery intake systems are a type of slow sand filter constructed

beneath the intertidal zone of the beach (Figure 3.6). The gallery is constructed with a series of

sand layers, fine at the top with a progressive increase in grain size with depth. The top layer is

constructed with the native sand on the beach so that it is compatible with it. The lowest layer is


40

gravel and is used as a support and water collection layer. Seawater is pumped from the bottom

layer using a header pipe and a series of screens, similar in concept to a seabed infiltration gallery

system (SIG). While slow sand filters rely upon gravity to operate, a beach gallery is pumped to

create suction head and pull the water through the filter. This pumping allows (a) adjustments to

be made to the infiltration rate, or (b) increases or decreases in suction pressure to be made, to

make the inflow rate constant.

A key aspect of a beach gallery system is that it underlies the surf zone of the beach, fully

or in part. This means that the active infiltration face of the filter is continuously cleaned by the

mechanical energy of the breaking waves and is therefore self-cleaning (Maliva and Missimer,

2010). Also, the location within the intertidal zone allows the gallery to be continuously

recharged with no impact on the inland shallow aquifer system.

The vertical flow of water from the sea assures that the inorganic chemistry is not

significantly altered over time. The water quality should remain relatively constant based on the

hydrology of the Huntington Beach area. The gallery system is unaffected by variations in the

deeper groundwater, which could be fresh or brackish in nature at the shoreline. The uppermost

natural sand layer is the primary treatment zone within the filter and will likely allow the removal

of all algae and a high percentage of bacteria and naturally occurring organic compounds (e.g.,

natural organic matter). The long-term data collected at the seabed gallery in Japan shows that the

SDI was reduced below two, which is at the approximate level produced by conventional SWRO

pretreatment systems (Shimokawa, 2012).

The beach gallery would reduce or eliminate the impingement and entrainment of marine

fauna. Also, upon completion of construction, the gallery would be located below the surface and

could not be observed by beach users.


41

Figure 3.6. Conceptual diagram of the beach gallery (from Maliva and Missimer, 2010). 3.4.3 Engineered seafloor infiltration galleries (SIGs) A seabed (or seafloor) gallery or seabed infiltration gallery (SIG) is constructed offshore

in a stable location. It is another engineered and constructed filter. It uses the concept of slow

sand filtration, and the uppermost layer is the part of the filter that contributes most to treatment

of the infiltrating water.

The largest SIG system in operation worldwide is the Fukuoka in Japan with a capacity

of about 27.2 MGD (Figure 3.7; Hamano et al., 2006; Shimokawa, 2012). A significant SIG test

facility has been constructed at the City of Long Beach, California (Wang et al., 2007; Wang et

al., 2009).

There are a number of different configurations that can be used in the design of a SIG

with implications for system reliability. The Fukuoka SIG has one collection pipe leading from

the pumping station on the coast to the offshore SIG. It is a single cell design with no backup

pump or means of conducting maintenance during operation. The operation of the Fukuoka SIG

has been very successful over the last eight years with no maintenance of the gallery surface and

production of seawater with a very low silt-density index (Shimokawa, 2012; Sesler and

Missimer, 2012), resulting in very infrequent cleaning of the membranes. The site is located in


42

sheltered water with lower wave heights and currents compared to the open-coast of Huntington

Beach. The plant site is subject to intense storm activity.

Figure 3.7. Fukuoka, Japan SIG conceptual diagram (from Pankratz, 2006). An important issue in the siting, design, and construction of a SIG is the bottom stability

and the robustness of the design to withstand any extreme natural events, such as earthquakes and

harmful algal blooms. The Fukuoka SIG operated without interruption through a 6.5 earthquake

on the Richter scale in 2005. The SIG showed only a short-duration increase in the silt density

index, but continued to provide high quality seawater to the SWRO plant.

To further increase reliability, SIGs can be constructed as modular systems using a series

of gallery cells, each equipped with a pump. This allows shorter distance collection systems to be

used to improve flow balance within the gallery and allows a high percentage of the SWRO

facility to operate in the event of a pump failure or some clogging of a cell. An example of a SIG


43

design with multiple cells is shown in Figure 3.8. Note that this preliminary design was for a very

large capacity SWRO facility (140 MGD) in Saudi Arabia.

The engineered filter used in a SIG contains multiple layers with an upper active layer

and several layers used that gradually reduce the grain size to transition into a basal, high

permeability collection layer (Figure 3.8). Similar to a beach gallery system, most of the water

treatment occurs in the upper layer.

Figure 3.8. Conceptual design of a SIG for the Shuqaiq SWRO plant, Red Sea, Saudi Arabia (from Mantilla and Missimer, 2014). 3.5 Water tunnels A tunnel intake was recently constructed to provide some or all of the 34.3 MGD of

feedwater required to operate the Alicante II SWRO plant in Spain (Rachman et al., 2014). This

system contains a tunnel underlying the beach area. The tunnel contains a series of collectors,

commonly drilled upward into the overlying aquifer (Figure 3.9). The laterals contain screens that

are open to the aquifer and yield water to the tunnel as it is pumped. It operates in a manner

similar to a vertical Ranney collector system.


44

The tunnel system lies fully beneath the surface and would have no significant

environmental impact during operations. The induced vertical flow of seawater would produce

water with a quality essentially identical to seawater and without inducing impacts to the shallow

aquifer landward of the beach. No information was provided by Poseidon on this option.

Figure 3.9. Conceptual diagram of a tunnel intake system proposed for another southern California SWRO plant. 3.6 Discussion The ISTAP considered various subsurface intake systems for use at the proposed 50

MGD capacity SWRO system at the City of Huntington Beach, California. Most subsurface

intake systems used at various global locations were reviewed. A common theme throughout the


45

world supporting the use of subsurface intake systems include: (1) reduced environmental

impacts, (2) production of feedwater of a higher quality compared to a conventional open-ocean

intake, (3) reduced potential for membrane biofouling, and (4) reduced operating costs.

At a very high infiltration rate (10 m/d) the water entrance velocity at the seawater/sea

bottom interface would be 0.0045 in/s. Therefore, no significant entrainment of marine organisms

would occur. No operational environmental impacts would, therefore, occur.

Subsurface intake systems tend to greatly improve feed water quality by reduction of SDI

and removal within the aquifer system or constructed filter of virtually all of the algae, up to 98%

of the bacteria, up to 50% of the natural organic matter with a higher percentage of organic

polymers removed, and a reduction of significant quantities of transparent exopolymer particles

(TEP) (Schwartz, 2003; Choules et al., 2007; Laparc et al., 2007; Rachman et al., 2014; Dehwah

et al., 2014). TEP is created by self-assembly of acidic polysaccharides secreted by algae and

bacteria (Passow, 2000). Organic biopolymers and TEP in the raw seawater conditions the

SWRO membranes and leads to membrane biofouling (Passou and Alldredge, 1994; Berman,

2012; Berman et al., 2011). Significant reduction in concentrations of biopolymers and TEP in

the feed water decreases the risk of membrane biofouling and tends to increase the time between

required membrane cleanings and allows longer operating life for the membranes (Vesa et al.,

2008). Thus, a subsurface intake may eliminate or significantly reduce the need for a pretreatment

system that would be needed to produce an equivalent RO feed water quality if a surface intake

were used with a standard water pretreatment system.

Use of higher feed water quality in a SWRO reduces the complexity of in-plant

pretreatment systems, thereby decreasing the usage of chemical, such as chlorine and coagulants,

reduces capital costs of constructing these systems, and reduces electric power consumption.

These factors tend to decrease the operating cost of SWRO water treatment (Wright et al., 1997;

Missimer et al., 2010) for subsurface intake systems.


46

Chapter IV. DISCUSSION OF FEASIBILITY CRITERIA 4.1 Introduction The technical feasibility of a subsurface intake type depends on a variety of

hydrogeological, design, oceanographic, and geochemical constraints. In addition, consideration

needs to be given to the historical experiences of the various intake types, and particularly

whether precedent exists for the investigated subsurface intake type, meaning that this type has

been constructed and successfully operated at a comparable scale and in a similar setting as the

studied Huntington Beach site. In order for a subsurface intake type to be considered technically

feasible at the Huntington Beach site, there must not be any fatal flaws, which are defined as

conditions that would either not allow a full-scale system to be successfully constructed and

operated or would result in a high risk of failure or unacceptable performance of Poseidon’s full-

scale target minimum hydraulic capacity of 100 MGD.

Following is a discussion of the feasibility criteria developed by the ISTAP to evaluate

the subsurface intake options described above at the Huntington Beach site. The application of

these criteria to the Huntington Beach site is presented in Section VII. Some criteria might not

lead to a fatal flaw from a purely technical perspective, but could impact feasibility from an

economic, regulatory, or environment perspective, whose consideration is not part of Phase 1 of

the ISTAP assessment. For example, low vertical well yields could require an uneconomically

large number of wells to obtain 100 or 127 MGD of seawater, and thus be economically

infeasible, whereas the option might still be technically possible.

Evaluation of the technical feasibility of the considered subsurface intake options

involved the collective professional judgment of the Panel as to whether or not the option could

be built and reliably operated using currently available methods. The application of professional

judgment involved consideration of the available data on the hydrogeology, oceanography, and


47

water quality of the Huntington Beach area and construction and operational experiences at other

sites.

4.2 Hydrogeological Feasibility Factor 4.2.1 Impacts on freshwater aquifers Groundwater pumping on the seaward site of the Talbert Gap could induce seaward flow

of water from the Orange County Groundwater Basin. The pumping of saline water could have

beneficial impacts as adding an extractive component to the Talbert Gap Salinity Barrier. The

pumping would tend to draw the saline-water interface seawards. However, large-scale

groundwater pumping seaward of the Talbert Gap may also result in abstraction of freshwater

from the basin, adversely impacting its water budget and causing additional drawdowns.

Subsurface intake options that would be expected to produce large volumes of water from the

Orange County Groundwater Basin would be considered fatally flawed.

4.2.2 Potential yields per installation Potential yields per installation are best estimates of unit yield per well, acre of gallery

subsurface area, and per foot of HDD well or water tunnel. In the absence of site-specific data,

these values were estimated based on local hydrogeology and the performance of similar systems

constructed elsewhere.

4.3 Design Constraints 4.3.1 Units required for 127 MGD The number of units (e.g., wells, gallery acres, feet of HDD wells) was obtained by

dividing the maximum hydraulic capacity of 127 MGD by the potential yield per installation. A

20% back-up (redundancy) factor was applied, which allows for system capacity to be maintained

during operation and maintenance activities and unexpected breakdowns of system components,

and some decline in performance over time.


48

4.3.2 Linear beachfront required Linear beachfront requirement gives an indication of how spread out a system will be and

is an important cost and logistical factor. The requirements were determined by multiplying the

number of units by anticipated minimum spacing. For example, a spacing of 100 feet was used

for vertical wells completed above the confining unit. Actual spacing requirements would be

determined through groundwater modeling to evaluate well interference. A 10-foot separation of

surf zone gallery cells is assumed.

4.3.3 Onshore footprint Onshore footprint is the area permanently required for the number of units. For vertical

wells, a 50-ft by 50-ft easement at the wellhead with a 10-ft by 200-ft pipeline easement are

assumed to be required. The estimated onshore footprints do not include temporary construction

easements. The offshore footprint of seafloor and surf zone infiltration galleries is determined by

the number of units required (Section 7.3.1).

4.3.4 Scalability Scalability refers to the ability to increase the capacity of the system. Subsurface intakes

inherently have a modular design, and capacity can be adjusted by changing the number of units.

Wells have estimated per well yields, and a specified project demand can be matched to the

required number of wells. Likewise, infiltration galleries have yields per unit area. Again, the

required demand for a project can be matched to the area required to supply that demand. Not

addressed are economies of scale, which is not in the TOR for Phase 1. In general, galleries, and

perhaps also water tunnels, tend to have relatively high economies of scale (i.e., there are unit

cost savings associated with constructing larger systems), whereas wells have a relatively low

economy of scale.


49

4.3.5 Complexity of construction Complexity of construction refers to the potential for difficulties to occur during

construction. It also ties into the local availability of contractors who are qualified to perform the

work and that have the specialty equipment and experience with this specific type of work.

Options that have a complex construction would be expected to be relatively expensive, of long

duration, and risky in terms of difficulties encountered during construction. Complexity of

construction, as considered herein, also includes consideration of factors that may impede or

delay construction including: uncertainties and extended duration for obtaining construction

permits, seasonal restrictions on beach construction due to public use, seasonal restrictions of

offshore operations due to sea conditions, and environmental impacts from construction.

4.3.6 Performance risk Performance risk is essentially the potential for the intake system to not meet project

performance expectations in terms of water yield and quality. It is one of the most important

factors in evaluating the technical feasibility of an intake option, as there must be confidence that

a constructed intake can satisfactorily perform over the 30-year planned minimum life of the

desalination plant. A high degree of uncertainty with regard to the likelihood of successful

implementation (i.e., a high potential for system failure or underperformance) is considered a

fatal flaw. Performance risk also relates to the opportunities to pilot test an intake option or

accurately estimate system performance using other means or data, including the operational

history of comparable systems constructed in similar geologies to Huntington Beach. For

example, vertical well intakes have a low performance risk because they can be readily pilot-

tested.

4.3.7 Reliability of intake system The reliability of an intake system considers whether or not, or the degree to which, an

intake option is expected to maintain acceptable performance over the planned lifespan of the


50

desalination plant. Typically, that lifespan for planning purposes is defined as 30 years, but longer

lifespan can be considered. The reliability of intake system factor allows for normal operation and

maintenance activities, provided that they can be readily performed and would restore system

performance. For example, vertical wells are expected to require periodic rehabilitation using

standard methods and replacement of pumps. Evaluation of the reliability of some intake options

is complicated by the absence of long-term operation data from precedent systems. The absence

of a precedent is of particular concern for system types that do not have precedence for use in

freshwater supply. For example, data are not available on the long-term performance of HDD and

slant wells, and whether or not they can be rehabilitated to close to original conditions.

4.3.8 Frequency of maintenance Frequency of maintenance is the relatively frequency at which an intake option is

expected to require operation and maintenance activities to either address breakdowns (e.g., pump

failure) or restore system performance (e.g., well rehabilitation).

4.3.9 Complexity of maintenance Subsurface intake systems are generally expected to require some maintenance over their

operational lives. Complexity of maintenance addresses both technical difficulties associated with

potential maintenance activities and logistical issues that may make maintenance more complex.

For example, rehabilitation of slant and HDD wells is much more complex than that of vertical

wells. Although potential maintenance of seafloor infiltration galleries is technically simple (e.g.,

raking the surface), it has a relatively high complexity because it is performed offshore.

4.3.10 Material constraints Material constraints address construction materials requirements for intake types. In

general, seawater intakes should be constructed of corrosion resistant materials.


51

4.4 Oceanographic constraints Oceanographic constraints address coastal sedimentological and environmental

constraints. Sea level change (rise) is of importance because it effects the position of the beach.

4.4.1 Sensitivity of sea level rise Sensitivity to sea level rise relates to the effects of changes in water depth and landwards

beach migration on constructed intakes. The location of intake structures needs to consider the

projected rise of seawater and beach migration over their operational lives. Intakes using wells

are designed and located with the intent of producing infiltrated seawater, with their optimal

location being as close to the shoreline (subtidal zone) as safely possible. Locating them further

inland to avoid the impacts of future sea level rise would place them now in a sub-optimal setting.

Intakes that require inundation (e.g., galleries and off-shore water tunnels) would not be sensitive

to a rise in sea level.

4.4.2 Sensitivity to Huntington Beach sedimentation rate Under normal conditions, Huntington Beach would be retreating due to erosion.

However, the beach is being maintained through artificial renourishment by the U.S. Army Corps

of Engineers. Sedimentation rate, whether natural or anthropogenically influenced, may impact

subsurface intakes by either burying or exhuming them. It is assumed that a SIG would be

installed in a sedimentologically stable area. The sensitivity of intake design option was evaluated

based on the projected Huntington Beach sedimentation rates and likely intake locations and

designs. Sedimentation rate is not applicable to vertical, slant, and radial collector wells.

4.4.3 Sensitivity to Huntington Beach bathymetry Sensitivity to Huntington Beach bathymetry addresses both current and potential post-sea

level rise future conditions. This factor is not applicable to vertical, slant, and radial collector

wells.


52

4.4.4 Suitability of bottom environment conditions Suitability of bottom environmental conditions is applicable to only seabed and surf zone

infiltration galleries. Unsuitable conditions would be a rocky bottom or the presence of sensitive

environments (e.g., kelp beds). The latter would constitute a fatal flaw.

4.5 Geochemical constraints Seawater desalination facilities using reverse osmosis technology require feed water with

a low suspended solids concentration, low concentrations of clogging organic compounds, and

stable water chemistry. Chemical conditions within the subsurface intake should also not be

conducive for biogeochemical clogging and associated loss of performance. The most stable

systems are those that produce only seawater from vertical infiltration. Mixing of waters with

different chemistries can result in a variety of adverse inorganic chemical reactions, such as

elemental sulfur and iron oxyhydroxide precipitation.

4.5.1 Risk of adverse fluid mixing The risks of adverse fluid mixing are greatest where waters from different directions

within an aquifer (landwards vs. seawards), aquifers, or aquifer depths enter an intake (or enter

different intakes and later mixing within piping system). Systems with the lowest risk of adverse

fluid mixing are constructed subsea and produce water largely by vertical infiltration.

4.5.2 Risk of clogging Loss of intake capacity by clogging (also referred to as plugging) can be caused by a

variety of chemical, biological, and physical processes. The greatest risk of clogging occurs

where there is mixing of dissimilar waters or a change in water chemistry (e.g., introduction of

dissolved oxygen). Clogging is of greatest concern where rehabilitation is complex and expensive

(Section 7.3.9).


53

4.5.3 Risk of changes on inorganic water chemistry Seawater desalination facilities are designed to treat water with a specific envelope of

chemical conditions. Long-term changes in water chemistry caused, for example, by different

fractions of landward derived freshwater could interfere with the reverse-osmosis process. The

risk is lowest where intakes produce water predominantly by vertical infiltration of seawater (e.g.,

subsea galleries).

4.6 Precedents Confidence in the feasibility of an intake option type is greatest where there is a track

record of successful implementation of the type at other sites with geological conditions similar to

Huntington Beach and ideally also of a comparable hydraulic capacity. Inasmuch as subsurface

intakes have a high scalability, the absence of precedents for the proposed 127 MGD system is

not considered to be a fatal flaw. However, problems (under-performance) at precedent systems is

an important consideration for evaluation of the technical feasibility of the intake option at

Huntington Beach, especially if there is no documentation of the cause and resolution of the

problem.


54

Chapter V. Evaluation of Subsurface Intake Types 5.1 Evaluation matrix An evaluation of the considered subsurface intake types with respect to the feasibility

criteria is provided as a coarse screening matrix in Table 5-1. Table 5-1 is based on the collective

professional judgment of the Independent Scientific and Technical Advisory Panel. The values of

the parameters used are best, ballpark estimates based on available local or general intake-type

information in the absence of site-specific actual data. It is important to stress that feasibility

issues did not closely depend upon the specific values used. For example, an increase or decrease

of well or gallery yields by a factor of two would not impact technical feasibility. However, well

or gallery yields are an important economic issue. The technical feasibility of each design option

is further discussed in Section 5.2. As noted elsewhere in this Report, the ISTAP stresses that the

evaluation was based on the hydrogeologic and oceanographic conditions specific to the

Huntington Beach AES site and proximate areas. The infeasibility of a particular intake type at

this location should not be generalized to feasibility assessments of any specific intake type in a

different setting or location.

5.2 Subsurface intake type feasibility at Huntington Beach 5.2.1 Vertical wells completed above upper confining unit Vertical wells have the lowest performance risk because their performance can be readily

determined through a test well program. The available information on the geology of the

Huntington Beach area indicates that the shallow aquifer is moderately transmissive (permeable),

which would limit well yields and increase the number of wells required to produce 127 MGD.

Assuming a well yield of 0.72 MGD/well, 212 wells would be required. A subsurface intake

system that requires such a large number of wells is technically challenging but not infeasible

(not taking cost into consideration), provided that well sites can be obtained. The 0.72 MGD (500


55

gpm) yield may be optimistic in terms of long-term pumping rates, and a lower well yield would

result in an even greater number of wells required. A more fundamental limitation is that a

production rate of 127 MGD is well beyond what is likely sustainable from the shallow aquifer.

As was noted by Mr. Roy Herndon of the OCWD during the public meeting, the proposed

groundwater pumping would be about 45% of the total Orange County Groundwater Basin

pumping. Pumping would result in very large drawdowns, which would pull freshwater from the

landward direction resulting in a high water quality risk. Vertical wells completed in the shallow

aquifer above the confining unit above the Talbert aquifer are thus considered to be infeasible.

5.2.2 Vertical wells completed below confining unit Large-scale water production from the Talbert aquifer would draw large volumes of

water from the landward direction, from the Orange County Groundwater Basin, which is

considered a fatal flaw rendering the option infeasible. Additional considerations are impacts to

the Talbert Gap salinity barrier, which could be net beneficial, and a geochemical risk from the

mixing of waters.

5.2.3 Vertical wells completed above and below confining unit Dual-zone aquifer would have the benefit of greater well yields, but would still have the

fatal flaw of a large component of the flow being derived from the Orange County Groundwater

Basin. Geochemical incompatibility would also be a major concern due to the mixing of waters

from two aquifers within the wells or piping system if paired wells were used.

5.2.4 Radial collector in shallow aquifer Radial (Ranney) collector wells have the advantage that large volumes of water

(equivalent to multiple vertical wells) may be produced from a single well site. Radial collector

wells are typically installed in hydrogeological settings where (a) high transmissivity interval(s)

is(are) present (e.g., gravel bed) in which laterals can be installed, rather than in sandy strata such

as present at the project site. Radial collectors are considered to have a medium performance risk


56

due to the very high cost of testing the option. A full-scale system would have to be constructed.

There are also practical limitations on the lengths of laterals. The driller does not

recommend/warranty laterals greater than 250 ft., which would mean the laterals would be

installed largely above the shoreline (rather than subsea), as caissons would have to be

constructed back from current high-tide line. Radial collector wells are considered technically

infeasible at the Huntington Beach site due to an inappropriate geology and because the

excessively high production rates from the shallow aquifer would not be viable.

5.2.5 Slant wells completed in Talbert aquifer Slant wells completed in the Talbert aquifer would draw large volumes of water from the

Orange County Groundwater Basin, which in itself is considered a fatal flaw. Recent public

comments have suggested that pumping seawards of the Talbert Salinity Barrier could have

beneficial impacts in managing seawater intrusion. In the Panel’s opinion, however, this benefit is

too uncertain to overcome the ISTAP conclusion about the fatal flaw of this technology as

applied to the proposed Huntington Beach site. The advantage of having a subsea completion is

largely lost in confined aquifers. The performance risk is considered medium, as the dual-rotary

drilling method used to construct the wells is a long-established technology, but there is very little

data on the long-term reliability of the wells. Maintainability is also a critical unknown issue.

5.2.6 Engineered seafloor infiltration galleries (SIGs) The results of the investigations by Scott Jenkins (as presented to the Panel) and others

indicate that an area with a stable seafloor is present off the Huntington Beach site that has a

relatively low environmental sensitivity. Inasmuch as the overlying sand materials can be

engineered to provide the target infiltration rate, and desired filtration performance and hydraulic

retention time, construction of an engineered seafloor infiltration gallery is considered to be

technically feasible. The limited precedence for this type of system (Fukuoka, Japan system) is

favorable as far as systems maintaining their capacity over time. However, the experiences at


57

Fukuoka are not necessarily transferable to Huntington Beach. The key consideration for a

seafloor infiltration gallery is construction complexity due to its construction offshore at depth.

Maintenance would also be complex, but not a fatal flaw. An engineered seafloor infiltration

gallery is thus considered to be technically feasible.

5.2.7 Surf zone infiltration galleries A surf zone infiltration gallery has the dual advantages of (a) construction near shore and

potential greater yields (per unit area) than a seafloor system due to a coarser grain size (and

greater hydraulic conductivity) and (b) the self-cleaning nature of the beach. However, the

construction complexity is high due to the high-energy breaking wave conditions in the surf zone.

In order to provide a safe work environment above the waves for equipment and crews

constructing the surf-zone infiltration gallery, all construction of the gallery would have to

performed from the top of a pile supported steel access trestle (temporary bridge) that would be

built over-the-top and elevated above the breaking waves.

The installation and advancement of such a trestle system is time-consuming and

expensive in that all work must be performed in a series of activities rather than concurrently as

performed in most normal marine construction operations. Work from the top of the trestle would

include construction of the trestle, installation of steel sheetpiles, dredging, installation of the

intake piping system, backfilling, extraction of sheetpiles, and finally removal of the trestle.

These operations could involve local beach closure of approximately 1500 feet of beach at a time

over a time period of approximately four to five years. In addition, the trestle and sheetpiles could

not be easily removed to allow timely public use of beach areas during summer seasons. Such

disruption to the environment and public use of extensive beach areas would create a very

difficult condition for obtaining construction permits from state and Federal regulatory agencies

within a reasonable and predictable time. Potential restrictions on the time of year in which

construction would be allowed would extend the construction period beyond that feasible for the


58

project. The combination of the above factors is considered to make a surf zone infiltration

gallery construction very challenging at the Huntington Beach site.

The length of construction along the beach would also impact littoral sand movement,

causing temporary local deposition and erosion as the gallery construction advances. However,

this impact on construction could be minimized by advancing construction of the gallery in a

down-coast or southward direction. A surf zone infiltration gallery would also be impacted by

periodic beach renourishment activities. Construction of a surf zone infiltration gallery is

considered to be technically feasible in that it is technically possible to construct such a system.

However, great constructability challenges would be expected, which would impact the ability to

meet project schedules and costs.

5.2.8 Horizontal directionally drilled (HDD) wells underneath the sea floor Horizontal directionally drilled (HDD) wells can technically be installed at the

Huntington Beach site, as the underlying technology is well established. The performance of the

HDD systems will be suboptimal in granular materials (sands) as opposed to lithified strata

(limestone) and thus a greater (undetermined) number of drains would be required. There is

inadequate data on the long-term reliability and maintainability of the HDD wells/drains at this

time. This subsurface intake design option is considered technically infeasible at the Huntington

Beach site because of a high performance risk. There is too great uncertainty that a system could

be constructed that would reliably provide the required water volume over the operational life of

the desalination facility.

5.2.9 Water tunnel A water tunnel constructed subsea would have the advantages of high water quality

stability and minimal impacts to the beach area. Water tunnels have severe construction

complexity as ground freezing may be required. Water tunnels are considered to be infeasible due


59

to a high performance risk. There is an unacceptable degree of uncertainty in the performance of

these systems, which cannot be practicably pilot-tested.


60

Subfactor




confining unit




aquifer


Talbert aquifer

Engineered seafloor



gallery


HydrogeologyImpact on fresh water aquifers Yes Yes Yes No Yes No No No No

Potential Yield per installation (MGD) 0.72 2.2 3 5

12.9 MGD per 3-well cluster3 5 MGD/acre 10 MGD / acre

0.67 to 2.2 MGD/drain1 2,600 GD/ft2

Design ConstraintsUnits required for 127 MGD with 20% safety factor

212 70 51 31 12 (3-well clusters) 30.48 acres 15.24 acres 227 to 69 drains 9 miles

Linear beachfront 4 miles 2 miles 1.4 miles 2 miles 1.3 miles 1.0 miles4 1.8 to 2.8 milesArea 2.2 acres5 0.7 acres 0.5 acres 0.3 acres 1.4 acres6 30.48 acres 15.24 acres 2.4 acres7 0.5 acresScalability Yes Yes Yes Yes Yes Yes Yes Yes YesComplexity of construction Low Low Low Medium Medium High High Medium Very High

Performance risk - degree of uncertainty of outcome

Low Low Low Medium Medium Medium Medium High Unknown

Reliability of intake system High High High Medium Medium/unknown Medium Medium/ unknown Unknown High

Frequency of maintenance High High High Medium High Medium/Unknown Medium/ unknown High Low

Complexity of maintenance Low Low Low Medium Medium High Medium High High

Material constraints

Non-metallic, sea water resistant. Duplex stainless steel pumps





HDPE/PVC HDPE/PVC


Pre-cast concrete/ss reinforcing. Laterals non-metallic

OceanographicSensitivity to sea level rise High High High High Medium Low Low Low Low

Sensitivity to HB sedimentation rate

N/A N/A N/A N/A N/A Low Low Low Low

Suitability of HB Bathymetry N/A N/A N/A N/A High High High High High

Suitability of bottom environmental conditions

N/A N/A N/A N/A N/A High High N/A N/A

Table 5-1 Subsurface Intake Summary Matrix


61

Subfactor




confining unit




aquifer


Talbert aquifer

Engineered seafloor



gallery


GeochemistryRisk of adverse fluid mixing Low High High Low High Low Low Unknown Low

Risk of clogging Low Medium High Low Medium Low Low Medium Low

Risk of significant change in inorganic chemistry of water quality over the long term?

High High High High High Low Low Medium Low

Precedent in use

Worldwide. Largest systems use (e.g., Sur, Oman) use carbonate aquifers. Sand City - 0.3 MGD is largest in sand.

Numerous brackish RO well fields

No precedent Ocean Beach, SF (Aquarium)

One test well (Dana Point). None in operation

Monterey Aquarium (small). Long Beach (small test).

Small scale systems

Eight systems installed mostly in Spain

Alicante, Spain

Precedent on large scale in similar geological conditions

Jeddah, Saudi Arabia; 5 MGD from 10 wells

No precedent No precedent

Pemex system in Mexico, 3 collectors with total capacity of 12 Mgd

No precedentFukuoka, Japan. 27 MGD intake capacity

No precedent

Alicante, Spain; designed for 34 MGD, operating at 17 MGD

Alicante, Spain, 17 MGD

Key considerations / fatal flaw(s)

Performance risk: inadequate aquifer capacity and great drawdowns. Low yields would require extremely high number of wells, major water quality risk



High performance risk due to inappropriate geologic conditions

Complications with seawater intrusion management and production from Orange Groundwater Basin; geochemical impacts

Construction complexity

Construction complexity in high energy environment, potential restrictions on allowable construction times/beach closure, impacts of beach renourishment

Performance risk concerns over granular materials and maintenance of well performance

Complex construction involving ground freezing. High performance risk - no precedence for project scale. Cost likely prohibitive

Technically Feasible? Y or N N N N N N Y Y N N

Table 5-1 Subsurface Intake Summary Matrix (Continued)


62

Table 5-1 Notes:

12.7 MGD average rage per drain for Alicante, Spain system, corrected for lower hydraulic conductivity at Huntington Beach 2Average rate for Alicante, Spain system 3Based on Dana Point test slant well 4Based on 150 ft. width by 300 ft. length cells and 30 ft. separation 5Assumed 250 ft. 2 per well; does not include construction easement 6Assumed 100 ft. by 50 ft. easement plus pipe line easement; does not include construction easement 7Assumed 300 ft. by 50 ft. easement plus pipe line easement; does not include construction easement, and seven clusters The judgments included in this Table are in response to the hydrogeologic and oceanographic conditions specific to the proposed HB AES site and proximate areas. The technical infeasibility of a particular intake technology at this location should not be generalized to feasibility considerations of any intake type in different settings or locations.


63

Chapter VI. Summary, Conclusions, and Recommendations for Phase 2 The ISTAP evaluated nine types of subsurface intakes for technical feasibility at the Huntington

Beach site. The subsurface feasibility options included: (1) vertical wells completed in the shallow aquifer

above the Talbert aquifer, (2) vertical deep wells completed within the Talbert aquifer, (3) vertical wells

open to both the shallow and Talbert aquifer, (4) radial collector wells tapping the shallow aquifer, (5)

slant wells tapping the Talbert aquifer, (6) seabed infiltration gallery (SIG), (7) beach gallery (surf zone

infiltration gallery), (8) horizontal directional drilled wells, and (9) a water tunnel.

The hydraulic design capacity for these subsurface intake types ranged from 127 MGD for the

combined requirement of the proposed SWRO plant and RO concentrate discharge dilution, and 100

MGD, if the concentrate discharge dilution was unneeded (diffuser system used to reduce environmental

impacts from the concentrate discharge).

The ISTAP used a standard definition of technical feasibility as defined in the California Coastal

Act and carefully evaluated fatal flaws of each subsurface intake type considered for application at the

proposed Huntington Beach site. Only the seabed infiltration gallery and the beach gallery survived the

fatal flaw analysis and both are deemed to be technically feasible at this site. The design of both types of

galleries is well understood, but construction challenges would be expected for both due to their

subsea/subtidal construction. The surf zone (beach) gallery, in particular, was judged to have some

potentially difficult constructability challenges (and thus a lesser degree of technical feasibility) related to

construction in the high-energy surf zone. The ISTAP does not consider the existing scale of use of any

particular subsurface intake compared to the capacity requirement at Huntington Beach to be a fatal flaw

for technical feasibility (e.g. the only existing seabed infiltration gallery has an hydraulic capacity of 27

MGD versus the 100 MGD proposed at the Huntington Beach site, and no large scale implementation of

the beach gallery has been constructed and operated to date).

It is the collective opinion of the ISTAP that each of the other seven subsurface intake options for

the desired hydraulic capacity range (100-127 MGD) had at least one technical fatal flaw that eliminated


64

it from further technical consideration. The shallow vertical wells would create unacceptable water level

drawdowns landward of the shoreline and could impact wetlands and cause movement of potential

contaminants seaward. The deep vertical wells would have a significant impact on the Talbert aquifer that

would interfere with the management of the salinity barrier and the management of the interior freshwater

basin. The combined shallow and deep-water wells would adversely impact both the shallow aquifer and

Talbert aquifer, and in addition, would produce waters with differing inorganic chemistry, which would

adversely affect SWRO plant operation. Radial collector wells constructed into the shallow aquifer would

have to be located very close to the surf zone which would make them susceptible to damage during

storms and would be impacted by the projected sea level rise. Slant wells tapping the Talbert aquifer

would interfere with the management of the salinity barrier and the management of the freshwater basin,

and further, would likely have geochemical issues with the water produced from the aquifer (e.g.,

oxidation states of mixing waters). The recently-collected offshore hydraulic conductively data shows that

the use of HDD wells is technically questionable and the largest capacity system in Spain is currently not

operating at its original design capacity. The water tunnel constructed in the unlithified sediment at

Huntington Beach would have overwhelming constructability issues.

The ISTAP recommends in Phase 2, further consideration be given solely to seabed infiltration

galleries (SIG) and beach gallery intake systems. For clarification, the ISTAP believes that the remaining

subsurface intake system deemed to be technically feasible could meet the seawater extraction goals of

either 100 or 127 MGD.

It is important to stress that the ISTAP interpreted its Phase 1 charge relative to the Terms of

Reference to be the evaluation of the technical feasibility of subsurface intake technology linked to a

proposal. Consistent with that approach, the Phase 1 Panel considered nine technologies keyed to a

potential project in the range 100 to 127 mgd. The Panel did address the broad issue of downward

scalability where they saw relevance, but did not consider a full or parsed range of scale options for any

of the nine technologies as this task exceeded the agreed upon scope defined in the TOR. Scalability


65

issues could be addressed in subsequent assessments of other feasibility factors at the mutual agreement

of the conveners.

Further, it was not the charge of the Phase 1 ISTAP to evaluate the economic considerations of

using a subsurface intake versus a conventional open-ocean intake in this phase. The ISTAP recommends

that the Phase 2 Panel give considerable analysis to the constructability of the seabed infiltration and

beach gallery intake systems, because this greatly affects the economic viability of their potential use.

However, the ISTAP recommends that in the Phase 2 evaluation of the subsurface intake options that a

detailed lifecycle cost analysis should be provided to the succeeding committee. This lifecycle cost

analysis should contain at least four scenarios, including: (1) the lifecycle cost using the appropriate

operating period duration obtaining the 127 MGD of feed water from a conventional open-ocean intake

without considering the cost of potential environmental impacts of impingement and entrainment, (2) the

lifecycle cost using the appropriate duration of an operating period obtaining the 127 MGD of feed water

from a conventional open-ocean intake and considering the cost of potential environmental impacts of

impingement and entrainment, (3) the lifecycle cost using the appropriate duration of an operating period

obtaining the 127 MGD of feed water from a seabed gallery intake system (or beach gallery intake

system) using the same pretreatment design as used in treating open-ocean seawater, and (4) the lifecycle

cost using the appropriate duration of an operating period obtaining the 127 MGD of feed water from a

seabed gallery intake system (or beach gallery intake system) using a reduced degree of pretreatment,

such as mixed media filtration followed by cartridge filters.

In each of these scenarios, the ISTAP recommends that the selected design hydraulic capacity

match both the minimum and maximum flow rates consistent with the desired production rate of a 50

MGD desalination facility using the SWRO technology. The definition of an “appropriate” operating

period should follow accepted industry standards for such lifecycle cost analyses. Typically, a period of

30 years is used, but given concerns on the potential for sea level rise impacts, analysis over a longer

operating period (e.g. 50 years) may be desirable. In addition, the ISTAP questions the need for the use of


66

seawater to dilute the concentrate discharge given the well-known use of diffuser outfalls to meet ocean

discharge requirements.

The ISTAP also recommends that “Technical Feasibility” should continue to be defined by

generally recognized factors as documented in the California Coastal Act of 1976. (Section 30108 of the

California Public Resources Code)


67

Chapter VII. Bibliography – Reports on Subsurface Intakes 7.1 Peer-reviewed publications, selected peer-reviewed conference papers, and books Allen, J. B., Tseng, T. J., Cheng, R. C., Wattier, K. I. (2008). Pilot and demonstration-scale research

evaluation of under-ocean floor seawater intake and discharge. Proceedings of the American

Water Works Association Water Quality Technology Conference, Nov. 16-20, 2008, Cincinnati,

Ohio.

Al-Mashharawi, S., Dehwah, A. H. A., Bandar, K. B., Missimer, T. M. (2014) Feasibility of using a

subsurface intake for SWRO facility south of Jeddah, Saudi Arabia. Desalination and Water

Treatment, Doi: 1080/19443994.2014.939870.

Amy, G., Carlson, K., Collins, M. R., Drewes, J., Gruenheid, M., and Jekel, M. (2006). Integrated

comparison of biofiltration in engineered versus natural systems. In: R. Gimbel, N. J. D. Graham,

and M. R. Collins (eds.), Recent progress in slow sand filtration and alternative biofiltration

processes. London, IWA Publishing, p. 3-11.

Barrett, J. M., Bryck, J., Collins, M. R., Jamois, B. A., Logsdon, G. S. (1991). Manual of design for slow

sand filtration. American Water Works Association Research Foundation and American Water

Works Association, Denver, Colorado.

Bartak, R., Grischek, T., Ghodeif, K., Ray, C. (2012). Beach sand filtration as pre-treatment for RO

desalination. International Journal of Water Science 1(2), 1-10.

Berman, T. (2010). Biofouling: TEP-a major challenge for water separation. Filtration & Separation

47(2), 20-22.

Berman, T., Mizrahi, R., Dosoretz, C. G. (2011). Transparent exopolymer particles (TEP): A critical

factor in aquatic biofilm initiation and fouling on filtration membranes. Desalination 276, 184-

190.


68

Choules, P., Schotter, J.-C., Leparc, J., Gai, K., Lafon, D. (2007). Operation experience from seawater

reverse osmosis plants. Proceedings, American Membrane Technology Conference and

Exposition, Las Vegas, Nevada, 2007.

Crittenden, J. C., Trussell, R. R., Hand, D. W., Howe, K. J., G. Tchobanoglous, G. (2005) Water

Treatment: Principles and Design. Hoboken, NJ, John Wiley & Sons.

David, B., Pinot, J.-P., Morrillon, M. (2009).Beach wells for large scale reverse osmosis plants: The Sur

case study. Proceedings of the International Desalination Association World Congress on

Desalination and Water Reuse, Atlantis, The Palm, Dubai, UAE, November 7-12, 2009,

IDAW/DB09-106.

Dehwah, A. H. A., Li, S., Al-Mashharawi, S., Winters, H., Missimer, T. M. (2014). Influence of beach

well and deep ocean intakes on TEP and organic carbon reduction in SWRO systems, Jeddah,

Saudi Arabia. Journal of the American Water Works Association (in press).

Dehwah, A. H. A., Missimer, T. M. (2013) Technical feasibility of using gallery intakes for seawater RO

facilities, northern Red Sea coast of Saudi Arabia: The king Abdullah Economic City site.

Desalination and Water Treatment 51 (34-36), 6472-6481, Doi: 10.1080/19443994.2013.770949.

Hamano, T., Tsuge, H., Goto, T. (2006). Innovations perform well in first year of operation. Desalination

and Water Treatment 16(1), 31-37.

Hendricks, D.W. (ed.) (1991). Manual of design for slow sand filtration. AWWA Research Foundation

and American Water Works Association, Denver, 247 pp.

Hendricks, D.W. (2011). Fundamentals of water treatment unit processes: Physical, chemical, and

biological. Boca Raton, CRC Press, 883 pp.

Huisman, L., and Wood, W.E. (1974) Slow sand filtration. World Health Organization, Geneva, 122 p.

Laparc, J., Schotter, J.-C., Rapenne, S., Croue, J. P., Lebaron, P., Lafon, D., Gaid, K. (2007). Use of

advanced analytical tools for monitoring performance of seawater pretreatment processes.

Proceedings of the International Desalination Association World Congress on Desalination and

Water Reuse, Maspalomas, Gran Canaria, Spain, October 21-26, 2007, IDAWC/MP07-124.


69

Lujan, L. R., Missimer, T. M. (2014) Technical feasibility of a seabed gallery system for SWRO facilities

at Shoaiba, Saudi Arabia and regions with similar geology. Desalination and Water Treatment,

Doi: 10.1080/19443994.2014.909630.

Maliva, R. G., Missimer, T. M. (2010). Self-cleaning beach gallery design for seawater desalination

plants. Desalination and Water Treatment 13(1-3), 88-95.

Mantilla, D., Missimer, T. M. (2014). Seabed gallery intake technical feasibility for SWRO facilities at

Shuqaiq, Saudi Arabia and other global locations with similar coastal characteristics. Journal of

Applied Water Engineering and Research, http://dx.doi.org/10.1080/2349676.2014.895686.

Missimer, T. M. (1994). Water supply development for membrane water treatment facilities, 1st edition.

Lewis Publishers, Boca Raton, Florida.

Missimer, T. M. (2009). Water supply development, aquifer storage, and concentrate disposal for

membrane water treatment facilities, 2nd edition. Methods in Water Resources Evaluation Series

No. 1. Schlumberger Water Services, Sugar Land, Texas.

Missimer, T. M., Ghaffour, N., Dehwah, A. H. A., Rachman, R., Maliva, R. G., Amy, G. (2013)

Subsurface intakes for seawater reverse osmosis facilities: Capacity limitation, water quality

improvement, and economics. Desalination 322, 37-51, Doi: 10.1016/j.desal.2013.04.021.

Missimer, T. M., Horvath, L. E. (1991). Alternative designs to replace conventional water-water intakes

for membrane treatment facilities. Proceedings of the International Desalination Association

World Congress on Desalination and Water Reuse, 131-140.

Missimer, T. M., Maliva, R. G., Thompson, M., Manahan, W. S., Goodboy, K. P. (2010). Reduction of

seawater reverse osmosis treatment costs by improvement of raw water quality, Innovative intake

design. Desalination & Water Reuse 20(3), 12-22.

Missimer, T. M., Winters, H. (2003). Reduction of biofouling at a seawater RO plant in the Cayman

Islands. Proceedings of the International Desalination Association World Congress on

Desalination and Water Reuse, Paper BAH03-190.


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Niizato, H., Inui, M., Kira, N., Inoue, T., Oiwa, T., Cai, H., Yanagimoto, Y., Nishimura, T. (2013).

Innovative SWRO desalination technology introducing high-speed seabed infiltration system

(HiSIS). Proceedings of the International Desalination Association World Congress on

Desalination and Water Reuse, October 20-25, Tianjin, China, Paper IDAWC/TIAN13-033.

Pankratz, T. (2006). Seawater desalination technology overview. Presentation to the Georgia Joint

Comprehensive Desalination Study Committee, August 22-23, 2006, St. Simons Island, Georgia.

Passow, U. (2000). Formation of transparent exopolymer particles, TEP, from dissolved precursor

material. Marine Ecology Progress Series 192, 1-11.

Passow, U., Alldredge, A. L. (1994). Distribution, size and bacterial-colonization of transparent

exopolymer particles (TEP) in the ocean. Marine Ecology Progress Series 113(1-2), 185-198.

Rachman, R. M., Li, S., Missimer, T. M. (2014) SWRO feed water quality improvement using subsurface

intakes in Oman, Spain, Turks and Caicos Islands, and Saudi Arabia. Desalination,

http://dx.doi.org/10.1016/j.desal.2014.07.032.

Schwartz, J. (2000). Beach well intakes for small seawater reverse osmosis plants. Middle East

Desalination Research Center Project 97-BS-015, August.

Schwartz, J. (2003). Beach well intakes improve feed-water quality. Water & Wastewater International

18(8).

Sesler, K., and Missimer, T. M. (2012) Technical feasibility of using seabed galleries for seawater RO

intakes and pretreatment: Om Al Misk Island, Red Sea, Saudi Arabia. IDA Journal: Desalination

and Water Reuse 4(4), 42-48.

Shimokawa, A. (2012). Fukuoka District desalination system with some unique methods. Proceedings of

the International Desalination Workshop on Intakes and Outfalls. National Centre of Excellence

in Desalination, May 16-17, 2012, Adelaide, Australia.

Vesa, M. J., Ortiz, M., Sadhwani, J. J., Gonzalez, J. E., Sanatana, F. J. (2008). Measurement of biofouling

in seawater: some practical tests. Desalination 220, 326-334.


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Voutchkov, N. (2005). SWRO desalination process: on the beach-seawater intakes, Filtration &

Separation 42(8), 24-27.

Voutchkov, N., 2005, Thorough study is key to large beach-well intakes: Desalination & Water Research,

v. 14, no. 1, p. 16-20.

Wang, S., Leung, E., Cheng, R., Tseng, T., Vuong, D., Carlson, D., Henson, J., Veerapaneni, S. (2007).

Under sea floor intake and discharge systems. Proceedings of the International Desalination

Association World Congress on Desalination and Water Reuse, Maspalomas, Gran Canaria,

Spain, October 21-26, 2007, Paper IDAWC/MP07-104.

Wang, S., Allen, J., Tseng, T., Cheng, R., Carlson, D., Henson, J. (2009). Design and performance update

of LBWD’s under ocean floor intake and discharge system. Proceedings of the Alden

Desalination Intake/Outfall Workshop, October 16, 2009, Holden, Massachusetts.

Williams, D. E. (2008). Research and development for horizontal/angle well technology, U.S Department

of the Interior, Bureau of Reclamation, Desalination and Water Purification Research and

Development Program Report No. 151.

Williams, D. E. (2012). Multiple advantages of slant wells for ocean desalination feedwater supply,

Abstracts and Program of the National Ground Water Association Summit.

Williams, D. E. (2014). Subsurface intakes-latest developments in slant well technology. Proceedings of

the AWWA/AMTA Membrane Technology Conference, Las Vegas, Nevada, March 10-13, 2014.

Williams, D. E., and Kyle, R. J., 2011, Utilization of subsurface slant and vertical intake systems for

desalination feed water supplies: Proceedings of the American Membrane Technology

Association Conference on Desalination and Exposition, Miami Beach, FL, 10 p.

Wright, R. R. Missimer, T. M. (1997). Alternative intakes for seawater membrane water treatment plants.

Proceedings of the International Desalination Association World Congress on Desalination and

Water Reuse, Madrid, Spain.


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7.2 Conference papers, reports and support documents

Feeney, M.B., 2009, Sand City Desalination Facility - Feedwater Wells Construction – Summary of

Operations Report. Consultant’s report prepared for City of Sand City.

Fugro West, Inc., 1996. Summary of Operations Construction and testing of Seawater Intake Well and

Brine Injection Well prepared for marina Coast Water District.

Geoscience, Inc. 2012, Aquifer Pumping Test Analysis and Evaluation of Specific Capacity and Well

Efficiency Relationships SL-1 Test Slant Well Doheny Beach, Dana Point, California Prepared

for: Municipal Water District of Orange County September 7, 2012.

Geosyntec Consultants, 2013. Feasibility assessment of shoreline subsurface collectors: Huntington

Beach seawater desalination project, Huntington Beach, California. Consultant’s report prepared

for Poseidon Resources.

Malfeito, J., and Jimenez, A., 2007, Horizontal drains intakes for seawater desalination-Experience of

Cartagena: Proceedings of the American Membrane Technology Association Conference on

Desalination and Exposition, Las Vegas, Nevada, 4 p.

MBC Applied Environmental Sciences, 2009, Huntington Beach Generating Station Environmental study

(exact report title unknown), Chapter 3 – Sediment characteristics: Consultants report to the

Huntington Beach Generating Station, 40 p.

Missimer, T. M., 1997, Technical evaluation of Ranney collectors for raw water supply to seawater

reverse osmosis treatment facilities: Proceedings, International Desalination Association World

Conference on Desalination and Water Reuse, Madrid, Spain, v. 1, p. 439-454.

Missimer, T. M., Manahan, W. S., and Maliva, R. G., 2010, Technical and economic analysis of intake

options for the proposed 70 L/s Tia Maria seawater RP treatment facility in southern Peru:

Proceedings of the American Membrane Technology Association Conference and Exposition,

San Diego, CA, 10 p.


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PSOMAS, 2011, Technical memorandum on feasibility of vertical extraction wells for Poseidon

desalination plant feed water supply: Consultants report to Poseidon Resources Corporation, 29

p., and appendices.

San Diego Regional Water Quality Board, 2007, Environmental evaluation of the Carlsbad desalination

facility, Chapter 4. Technology, 27 p.

Staal, Gardner, and Dunne, 1992. Feasibility Study Saline Ground Water Intake System, Monterey Sand

Company Site, Marina, California, California prepared for the Monterey Peninsula Water

Management District.

Taylor, J. M. C., and Headland, 2005, Analysis and design of infiltration seawater intakes: Proceedings,

American Society of Civil Engineers World Water Congress, Impacts of Global Climate Change.

World Water and Environmental Resources, May 15-19, Anchorage, Alaska, 12 p.

Tenera Environmental, 2006, Offshore survey at Huntington Beach generating station intake and

discharge structures: Consultants report prepared for the AES Huntington Beach Generating

Station, 16 p.

U.S. Department of the Interior Bureau of Reclamation, 2009, Desalination and Water Purification

Research and Development Program Report No. 152, Results of Drilling, Construction,

Development, and Testing of Dana Point Ocean Desalination Project Test Slant Well, January

2009 , Prepared by Geoscience, Inc.

7.3 Posted literature

California Coastal Commission (2004). Seawater Desalination and the California Coastal Act (2004) – in

particular, Chapter 2.2.1 (on feasibility) and Chapter 5.5.1 (on intakes):

http:www.coastal.ca.gov/energy/14a-3-2004-desalination.pdf.

Edwards, B.D., Ehman, K. D., Ponti, D. J., Reichard, E. G., Tinsley, J. C., Rosenbauer, R. J., Land, R.

(2009). Stratigraphic controls on saltwater intrusion in the Dominguez Gap area of coastal Los


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Angeles. In: Lee, H.J., W.R. Normark (eds.), Earth Science in the Urban Ocean: The Southern

California Continental Borderland. Geological Society of America Special Paper 454, p. 375-395.

Herndon, R. 1992. Hydrogeology of Orange County Ground Water Basin – An Overview. In: Heath,

E.G., Lewis, W. L. (eds.) (1992). The Regressive Pleistocene Shoreline – Southern California.

South Coast Geological Society, Inc. Annual Field Trip Guide Book No. 20.

Missimer, T. M., Ghaffour, N., Dehwah, A. H. A., Rachman, R., Maliva, R. G., Amy, G. (2013)

Subsurface intakes for seawater reverse osmosis facilities: Capacity limitation, water quality

improvement, and economics. Desalination 322, 37-51, Doi: 10.1016/j.desal.2013.04.021.

Orange County Water District (OCWD) (2009). Groundwater Management Plan 2009 Update GWMP.

July 2009.

Sommerfield, C.K., Lee, H. J., Normark, W. R. (2009). Postglacial sedimentary record of the Southern

California continental shelf and slope, Point Conception to Dana Point. In: Lee, H.J., Normark,

W. R. (eds.), Earth Science in the Urban Ocean: The Southern California Continental Borderland,

Geological Society of America Special Paper 454, p. 89-115.

Water ReUse Association (2011). Assessing seawater intake systems for desalination plants, 2011.

Wong, F.I., Dartnell, P., Edwards, B. D., Phillips, E. L. (2012). Seafloor geology and benthic habitats,

San Pedro Shelf, southern California. U.S. Geological Survey Data Series 552.

http://pubs.usgs.gov/ds/552/


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Chapter VIII. APPENDICES 8.1 APPENDIX A: Biographies of Panelists

Robert Bittner, P.E.

Mr. Robert Bittner is a professional engineer and President of Bittner-Shen Consulting Engineers,

Inc., a firm specializing in the design of innovative marine structures including bridge foundations,

marine terminals, offshore GBS structures, locks and dams. He has 40 years experience in construction

engineering and project management on major marine structures worldwide, including the Itaipu Dam in

Brazil and the Oresund Tunnel connecting Denmark and Sweden. One focus of his work has been

minimizing construction cost of major marine structures through the design and development of

innovative construction methods and equipment.

Prior to starting his own firm in 2009, Mr. Bittner was President of Ben C. Gerwick, Inc. While at

Gerwick, he provided construction-consulting services worldwide and managed the design of several

marine structures, including an innovative float-in dam on the Monongahela River in Pennsylvania for the

US Army Corps of Engineers. Additionally, he led the Gerwick team that developed a new float-in

cofferdam system that has been successfully used on the foundations for the New Carquinez Straits

Bridge in the San Francisco Bay Area, the New Bath-Woolwich Bridge in Maine, the new Port Mann

Bridge in Canada, and three major bridges in Asia. Mr. Bittner was Chairman of the Marine Foundations

Committee for the Deep Foundations Institute (DFI) for 6 years from 2003 to 2008, and is currently

President of DFI.

Mr. Bittner holds a B.S. in Civil Engineering and an M.S. in Construction Management, both

from Stanford University.

Martin Feeney, PG CEG CHg

Martin Feeney is an independent consultant providing hydrogeologic support services to

municipalities, water agencies and water utility companies. Mr. Feeney is a California Professional

Geologist with specialty certifications in engineering geology (CEG) and hydrogeology (CHg) and has


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more than 30 years experience in groundwater consulting. Mr. Feeney was a founding Principal of Staal,

Gardner and Dunne, Inc. (later becoming Fugro West, Inc.) and managed this firm’s Monterey County

office for nine years. He was later was a member of the firm, Balance Hydrologics, Inc. Mr. Feeney’s

experience in groundwater supply issues includes basin analysis, well siting and design, groundwater

modeling (both flow and solute-transport), perennial yield analysis, water quality assessments, and

regulatory compliance.

During his career, Mr. Feeney has designed and managed the construction of over 120 municipal

wells with depths to 2,500 feet, diameters to 24-inches and discharge rates of up to 6,000 gpm. He has

significant experience in drilling and well construction technology as well of the assessment and

rehabilitation of existing wells. Mr. Feeney also has significant experience in groundwater issues

associated with desalination facilities. He has worked in the Caribbean on numerous subsurface feedwater

supply systems and was instrumental in the development of the feedwater and reject disposal systems

utilized in the desalination facilities in Marina and Sand City, CA. Mr. Feeney has been involved in the

evaluation of subsurface feedwater supply feasibility on beaches of Ventura, Monterey and San Diego

Counties. These evaluations include alternative subsurface feedwater supply approaches including

vertical wells, Ranney Collectors, horizontal wells and slant wells.

Mr. Feeney has participated in several peer review advisory panels. Currently, he is a member of

the so-called “Hydrogeologic Working Group” evaluating the feasibility and potential water rights

impacts of the installation of a 24 MGD capacity slant well array on the edge of Monterey Bay to support

a regional desalination facility. Mr. Feeney is also currently is a member of the DPH-mandated

Independent Advisory Panel for the Monterey Regional Water Quality Control Agency’s Groundwater

Replenishment project utilizing highly treated wastewater for groundwater recharge. He has previously

served on advisory panels focusing on the overdraft issues in the Salinas and Pajaro Valleys, the sewer

system in Los Osos and groundwater management plan development in the Carpenteria Basin. He has a

BS in geology (UCSC) and a MA in Environmental Planning -Groundwater Emphasis (UCD, CSUN).


77

Michael C. Kavanaugh PhD, P.E., BCEE

Dr. Michael Kavanaugh is a professional engineer and Senior Principal with Geosyntec

Consultants, Inc. He is a registered professional engineer in California, a Board Certified Environmental

Engineer (BCEE), and an elected Fellow of the Water Environment Federation. Dr. Kavanaugh has over

40 years of consulting experience advising private and public sector clients on water quality, water and

wastewater treatment, and groundwater restoration issues.

In addition to his consulting practice, Dr. Kavanaugh has broad experience in science advising for

policy. He completed several assignments with the National Research Council including chair of the

Water Science and Technology Board and the Board on Radioactive Waste Management. He also chaired

the NRC committee on alternatives for ground water cleanup (1994) and recently chaired a NRC study on

the future of subsurface remediation efforts in the U.S. with a report released 2013. For the past ten years,

he has been a regular contributor to the Princeton Groundwater professional courses offered in the U.S.

and Brazil. Dr. Kavanaugh was elected into the National Academy of Engineering (NAE) in 1998.

He has a B.S. and M.S. degrees in Chemical Engineering from Stanford and the University of

California, Berkeley, respectively and a PhD in Civil/Environmental Engineering from UC Berkeley.

Robert G. Maliva, Ph.D.

Dr. Robert Maliva is a hydrogeologist and is currently a Principal Hydrogeologist with

Schlumberger Water Services USA, Inc. based in Fort Myers, Florida. Dr. Maliva specializes in

alternative water supply projects including managed aquifer recharge, alternative intakes for desalination

systems, and injection well systems used for the disposal of desalination concentrate and other liquid

wastes. He has been a consulting hydrogeologist since 1992.

Dr. Maliva has managed or taken the technical lead on numerous water resources and hydrologic

investigations including water supply investigations, wellfield designs, aquifer storage and recovery

(ASR) projects, contamination assessments, and environmental site assessments. He has designed raw


78

water supply wellfields for brackish water desalination systems, alternative intakes for seawater

desalination systems, and injection well systems for concentrate disposal.

He is the senior author of two books, “Aquifer Storage and Recovery and Managed Aquifer

Recharge Using Wells: Planning, Hydrogeology, Design, and Operation” (2010) and “Arid Lands Water

Evaluation and Management” (2012), and has numerous peer-reviewed publications. Dr. Maliva has a

Ph.D. from Harvard University and has held research positions in the Department of Earth Sciences at the

University of Cambridge, England, and the Rosenstiel School of Marine and Atmospheric Science of the

University of Miami, Florida. He also has an A.M. in Geology from Indiana University at Bloomington,

Indiana and a B.S. in Geology from State University of New York at Binghamton, New York, USA.

Thomas M. Missimer, Ph.D.

Dr. Thomas Missimer is a hydrogeologist and president of Missimer Hydrological Services, Inc.,

a Florida-based consulting firm. He is licensed as a professional geologist in four states. Dr. Missimer is

also a visiting professor of environmental science and engineering (specialty in hydrogeology) at the King

Abdullah University of Science and Technology in Saudi Arabia and is currently a visiting professor at

the U. A. Whitaker College of Engineering, Florida Gulf Coast University.

He has 41 years of experience as a hydrogeologist and has completed projects in groundwater

development, water resources management, and the design and construction of various water projects. He

has worked on a large number of artificial aquifer recharge projects used for storage and treatment of

impaired waters (domestic wastewater and stormwater) and for seasonal and strategic storage of potable

water (aquifer storage and recovery projects). He is the author of nine books and more than 350 technical

papers of which about 80 are published in peer-reviewed journals.

Dr. Missimer has specialized in the design, permitting, and construction of intake systems for

brackish-water and seawater reverse osmosis desalination systems. His book entitled “Water supply

development, aquifer storage, and concentrate disposal for membrane water treatment systems”

(Schlumberger, 2009) is a widely used reference in this field and has won two publishers awards in


79

technical communication. His first wellfield project used to supply feed water for an RO system was

completed in 1977, and he has worked on over 80 other systems worldwide. He and his students have

completed and published 6 technical feasibility investigations over the last three years along the

shorelines of the Red Sea and Arabian Gulf to assess the use of seabed gallery intake systems. In 1991, he

won the best paper presentation award from the International Desalination Association for his paper on

use of subsurface intake systems to supply large-capacity seawater desalination systems.

He has a BA in geology from Franklin & Marshall College, an MS in geology from Florida State

University, and a PhD in marine geology and geophysics from the University of Miami.

--------------------

FINAL- Apri/18, 2014

Terms of Reference for an Independent Scientific and Technical Advisory Panel (ISTAP)

to Examine the Feasibility of Subsurface Intakes and Advise the California Coastal Commission on Poseidon Water's Proposed Huntington

Beach Desalination Project April18, 2014

Headings Included Here A. Background B. Mission Statement and Purpose C. Criteria to Guide the Panel's Assessment of Feasibility D. Initial Work Program E. Qualifications and Recruitment Criteria for Panel Members F. Method of Panel Recruitment G. Administrative Arrangements/Operating Procedures H. Meeting Formats I. Authorship Attribution, Distribution and Dissemination of the Panel's Report J. Final Report as Part of Public Record K. Statement of Concurrence

A. Background As part of its review of a permit application from Poseidon Resources to construct and operate a desalination facility in Huntington Beach, the California Coastal Commission directed the applicant to undertake a more complete independent analysis of intake alternatives. Due to concerns over impacts on the coastal environment and marine ecosystems [Coastal Act Sections 30230 and 30231 in particular], the Commission recommended that Poseidon examine in more detail the feasibility of subsurface intakes.

In order to establish a review process that is responsive to the Commission's guidance and appropriately engages Poseidon, both parties have agreed to undertake an independent scientific review, To help implement this guidance, Poseidon has agreed to contract with CONCUR, Inc., a firm specializing in analysis and resolution of complex environmental issues and in structuring independent review processes. Vv'hile the Commission is not contracting with CONCUR, the agency staff agrees on the choice of CONCUR as the facilitator and convener of this independent review.

This Terms of Reference document (TOR) sets the structnre and operating procedures of the scientific review and sets the specific charge to the Panelists. The intention of this Terms of Reference is that, while Poseidon and the agency staff may have some divergent interests, they wilt collaborate and strive to reach agreement on these elements of the review process.1

1 In this TOR, Poseidon Resourc-es (Surfside) LLC will be referred to simply as "'Poseidon", the term '"Commission" refers to the agency and its governing board, and the staff of the Coastal Commission will be referred to a~ "agency staff'. The tenn ;'both parties" means Poseidon and agency staff.

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CONCUR will convene a panel of scientific experts-the Independent Scientific and Technical Advisory Panel-to review the issues at hand and make recommendations to bolster the scientific underpinning of the permit application and review process.

Both parties agree that this "joint fact-finding process" is a credible and effective way to respond to the guidance provided by the Commission. The Panel will consider a defined set of questions, deliberate, and prepare reports that will be delivered to both parties. These reports will provide evidence for the Commission and agency staff to consider when staff prepares its recommendation to the Commission regarding the proposed project The Panel's final reports will be part of the Commission's record for Poseidon's permit application.

B. Mission Statement and Purpose The broad goal of the Independent Scientific and Technical Review Panel is to provide credible, legitimate and independent scientific advice and guidance to support permit review.

The Panel's specific and limited purpose is to investigate whether alternative intakes would be a feasible method to provide source water to Poseidon's proposed desalination facility. It will focus on the extant site at Huntington Beach, but may investigate alternate sites on the Orange County coast. If subsequent phases of work are initiated, the expectations are that the Panel will compare the relative degree of feasibility of alternative intakes as described below.

Poseidon will fund the Panel and CONCUR. To ensure the Panel's independence, it will be guided by CONC1.JR and will report directly to agency staff with input from but without alteration by Poseidon. To provide transparency, the public will be invited to participate in some Panel meetings (but not Panel work sessions) and to comment at intervals on the Panel's interim and final work products for each phase of work as may be undertaken.

C, Criteria to Guide the Panel's Assessment of Feasibility Both parties will set forth criteria they find important to the consideration of "feasibility" as defined in the Coastal Act, which will be reviewed and considered by the Panel in determining the feasibility criteria to he used for each phase that is undertaken.

D. Initial Work Program The scope of work may include one or more phases as set forth below.

After each phase, both parties will consider the results of the phase and advise on next steps.

Both parties agree that the intent of the review is to work through to a final product for each phase that is undertaken. Both parties commit to at least the first phase of work outlined. Both parties would need to concur to go beyond Phase I and involve the Panel in later phases. Both parties anticipate that the disciplines composing the Panel would need to be rethought between Phase I and Phase 2. The disciplinary composition ofthe Panel may be revised at each phase to provide the necessary expertise.

Both parties agree that multiple phases will be necessary to generate the information the Commission needs to proceed to a final decision.

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FINAL- April/8, 2014

The Phase I scope of work is as follows:

Phase I: Technical FeasibiliD'J!!. Huntingto11J::leach.2 Investigate whether alternative subsurface intake designs would be technically feasible at the proposed site at Huntington Beach. This assessment of technical feasibility will include a characterization of the geophysical, hydrogeological and geochemical features of the site and will identify the expected size and hydrogeological effects of the range of subsurface intakes that could be accommodated on the site, including those that could provide source water for the proposed 50 mgd facility. For Phase I, both parties agree that the working definition of technically feasible is: able to be built and operated using currently available methods. This phase will include gaining command ofthe project and context, clarification of the goals and scope of this phase, review of published literature, case reports, and on-site studies. The Panel would prepare a report at the end of this phase that describes technically feasible alternative intake designs at or near the site and may also be asked to prepare interim informal reports.

At the end of Phase 1, both parties would consider the Panel report and the makeup of the Panel needed for the next Phase. Based upon the discussions to develop the Phase I scope of work, both parties have developed the following scope of work for Phase 2, if both parties decide to initiate a second phase.

Phase 2: Additional Review of Components of Feasibility at HuntingtQ!!Beach. Still focused on the Huntington Beach site, the Panel would characterize the technically feasible subsurface intakes identified in Phase I relative to a broader range of evaluation criteria, as recommended by the parties and determined by the Panel, such as size, scale, cost, energy use, and characteristics related to site requirements and environmental concerns consistent with the Coastal Act's definition of feasible, and as compared to the proposed open intake. The Panel would prepare a report at the end of this Phase and may also be asked to prepare interim informal reports.

Both parties will decide after Phase 2 whether to conclude the IST AP or whether to conduct additional studies and review. For instance, if initial review indicates that constructing a subsurface intake at the Huntington Beach site may not be feasible, a potential third phase could consider other locations on the Orange County Coast that might offer superior conditions for construction of subsurface intakes. The Panel could perform a recol1llftissance-level review to identify alternative sites that should be the subject of a more in-depth analysis by the Panel or others and studied concurrently or at a later date. This reconnaissance level review should be considered a coarse screening. A fourth phase may entail a more in-depth analysis of alternate sites and if the ISTAP is involved may require additional expertise.

E. Qualifications and Recruitment Criteria for Panel Members In Phase 1, the Panel is expected to include disciplines that as a whole should provide coverage of all of the following areas:

2 The parties are aware that State Water Board staff is developing an amendment to the Ocean Plan that would address issues

a~sociated with desaHnlzatmn tadlities. The parties intend that the ISTAP process Vttould be ahle to receive briefings on the progress and outputs of the SWRCB process (perhaps with State Board staff as technical advisors to this process).

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FINAL-April 18,2014

o Subsurface intake design, construction, and/or operation o Geophysical and/or hydrogeological study design and modeling o Coastal processes and/or physical oceanography- hydrodynamics, sediment transport,

sediment characterization, etc. o Coastal engineering/construction methods/cost analysis o Geophysical and/or hydrogeological characteristics of Orange County coastal areas o Groundwater geochemistry

At each later phase both parties will work to define needed qualifications and disciplinary recruitment criteria. Other later phases of the Panel may include such disciplines as marine ecology or cost-benefit analysis.

Additional Recruitment Criteria Panel members should possess demonstrated aptitude and capability in the following areas:

o Able to operate as an independent expert representing their professional discipline and experience in their participation in this IS TAP

o Experience providing scientific advice for developing public policy o Ability to integrate multiple disciplinary perspectives o Experience with highly contentious issues and high stakeholder interest o Experience preparing reports for policy audiences o Availability to work in a team setting o Willingness to work with the expectation that the Panelists will author the report, accept

attribution to the entire report, and sign the final report (Note: CONCUR will support the drafting and production of the report in all stages of work.)

Method of Panel Selection Both parties, working with CONCUR, will jointly select the Panel. The credentials of potential members will be considered on their merits relative to the selection criteria listed above.

F. Technical Advisors Individuals may also be considered for a potential Technical Advisor role. It is expected that a small number of Technical Advisors may be asked to make short presentations to contribute to the deliberations of the Panel and provide additional detail and context to support the Panel's work. It is understood that Technical Advisors are not expected to meet the Panelists' rigorous criteria for independence. Technical Advisors are not expected to participate in the entire duration of the Panel's work, but may be called in for specific topics. Technical Advisors will not participate in the internal Panel deliberations, nor will they be asked to co-author or co-sign the final Panel report.

G. Method of Panel Recruitment Both parties will consider criteria for the recruitment of Panelists and will use their professional networks to identify and suggest potential candidates. CONCUR will also use its professional network and make suggestions for potential candidates. Together, all parties will form a pool of candidates, which the agency staff, Poseidon, and CONCUR will jointly review with the aim of reaching agreement on the full Panel.

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FINAL- April 18, 2014

H. Administrative Arrangements and Operating Procedures Both parties agree to the following provisions to ensure proper administration of the independent Panel:

I. Poseidon will provide funds to CONCUR, Inc. in advance of convening the Panel in an amount outlined by the Scope of Work developed by the facilitator.

2. Panel members will be remunerated by CONCUR, with the panelist's client understood to be the ISTAP.

3. Poseidon and agency staff will work with the facilitator to draft and proceed jointly to agree to the Terms of Reference (TOR). By mutual agreement of all parties, supplemental Terms of Reference may be incorporated at a later time.

4. The Panel, once constituted, will be asked to verbally communicate with Poseidon or agency staff only with representatives of both parties participating via the facilitator (or with cc 's to CONCUR). Questions or comments (including requests for additional information, data, or documents) should be stated in writing, with copies to both parties.

5. The Panel's work products are to reflect its independent scientific and technical judgment. Both agency staff and Poseidon will contribute information and review, but neither agency staff nor Poseidon will alter the work products, and there will be clear identification as to their independent status. Both parties will not alter work products, but will have opportunities to comment on draft work products, as will members of the public.

6. Questions will be posed to the Panel via a written program of work and supplementary memoranda. The Panel will respond with written statements, which may be supplemented with briefings.

7. CONCUR shall designate Principal Scott McCreary as the facilitator for directing the activities of the Panel and as the point of administrative contact. The Poseidon point of contact is Stan Williams. The Coastal Commission point of contact is Tom Luster.

8. The Panel's formal contacts with agencies, stakeholders and the public will be via procedures established through the Terms of Reference in consultation with Poseidon, agency staff, and CONCUR to strike a balance between the Panel's independence and ensuring fair and open access to the Panel and its work products.

I. Meeting Formats Meetings of the Panel will be of three types:

• Panel meetings with structured opportunities for observers, representatives of agencies, and Technical Advisors (as described in F. above) to hear and make presentations and public comments.

• Work sessions, where the Panel may interact with invited Technical Advisors • In person or by-telephone work sessions of the Panel.

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FINAL- 1014

CONCUR will prepare summaries of deliberations of all meetings. Summaries will be made available to the public. CONCUR will be the primary point of contact for handling press inquiries. Agency staff and Poseidon may consider the use of short, joint statements at intervals.

Panel members "Will need to review critical Commission and other documents so that their comments and recommendations are based on:

• The best possible understanding of the physical requirements of desalination, local land use conditions and limitations, marine ecosystems in the region of the proposed project;

• An understanding of the policy and administrative context of Commission deliberations; • The timelines and targets tor Commission permit review and related actions; • The timelines and targets for Poseidon's corporate planning.

J. Authorship, Attribution, Distribution and Dissemination ofthe Panel's Report The expectation is that Panel members will author, accept attribution, and sign the final report in its entirety. The Panel will submit the results of its review to Poseidon and agency stafi simultaneously. If requested, the Panel may present the findings of its report in a Workshop format or briefing to the Commission.

K. final Report Becomes Part of the Public Record Upon its presentation, this Report becomes part of the public record.

L. Statement of Concurrence We hereby concur and agree to this Terms of Reference document and funding requirements as described in this document.

Poseidon Resources (Surfside) LLC:

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